How to add a signature in Gmail
Updated 21 July 2026 · 9 min read · Desktop, Android and iPhone
In Gmail on a computer, open Settings → See all settings → General, scroll to Signature, select Create new, name it, type or paste your signature, then set it under Signature defaults and select Save Changes at the bottom.
The Gmail mobile app keeps a completely separate signature that only accepts plain text. If you want your formatted desktop signature on your phone, the fix is counterintuitive: turn the mobile signature off.
- Creating a signature does not switch it on. You must also select it under Signature defaults, where two separate dropdowns both start on “No signature”.
- Desktop and mobile signatures are stored separately. Setting one has no effect on the other.
- The mobile app accepts plain text only — no images, bold, colours or clickable links.
- Turning the mobile signature off makes the app fall back to your formatted web signature, which is the opposite of what most people try.
- Gmail caps signatures at 10,000 characters of HTML, not visible text, which is why a short-looking signature can still be rejected.
Adding a signature in Gmail on desktop
Gmail has no desktop application, so this is the same on Windows, macOS and Linux — everything happens in the browser at mail.google.com.
- Open Gmail and select the gear icon in the top right, then See all settings.
- Stay on the General tab and scroll down to the Signature section. It sits a long way down the page, past the language, density and stars settings.
- Select + Create new. Give the signature an internal name — something like “Work” or “Client-facing”. Recipients never see this name.
- Type your signature in the editor, or paste one in. The toolbar gives you bold, italic, text colour, links and image insertion.
- Under Signature defaults, choose which signature applies to new emails and which applies to replies and forwards. These are two separate dropdowns and both default to “No signature”.
- Scroll to the very bottom and select Save Changes. Gmail discards everything if you navigate away without doing this.
Creating a signature does not switch it on. Until you set it under Signature defaults, both dropdowns stay on “No signature” and nothing appears on your messages. This is the single most common reason a Gmail signature does not show up.
Choosing whether it appears on replies
Directly under the defaults you will find Insert signature before quoted text and remove the “–” line that precedes it. Leave it unticked and your signature sits at the very bottom of a long reply chain, below all the quoted history. Tick it and your signature appears directly under your new text, where people actually read. On a long thread, ticked is almost always the better choice.
Adding a signature in the Gmail mobile app
This is where Gmail behaves in a way that surprises almost everyone. Your desktop signature and your mobile signature are stored separately, and the mobile field accepts plain text only — no images, no logos, no bold, no clickable links, no colours.
Gmail app on Android
- Tap the three lines top left to open the menu, then scroll down to Settings.
- Tap the account you want to change.
- Tap Mobile Signature.
- Type your text and tap OK.
Gmail app on iOS
- Tap the three lines top left, then Settings.
- Tap the account you want to change.
- Tap Signature settings, then switch Mobile Signature on.
- Type your text. Changes save automatically.
If you leave Mobile Signature turned off, the app falls back to the formatted signature you set on the web — logo, links and all. A mobile signature, once set, overrides it. So the way to get your good signature onto your phone is to delete the mobile one rather than write a better one. This landed on iOS first and reached Android later, so send yourself a test message to confirm it works on your device and app version.
Worth remembering that a signature designed for a 27-inch monitor rarely reads well on a 390px phone screen. If you do keep a separate mobile signature, three lines is plenty: name, role, and one phone number.
Gmail’s Signature section sits well down the General tab. The two Signature defaults dropdowns underneath are what actually switch a signature on.
What each Gmail platform supports
Gmail is really four separate signature systems that do not talk to each other. Knowing which one you are editing explains most of the confusion.
| Capability | Gmail web | Android app | iOS app | Mobile browser |
|---|---|---|---|---|
| Rich formatting (bold, colour, size) | Yes | No | No | Limited |
| Images and logos | Yes | No | No | No |
| Clickable links | Yes | No | No | Limited |
| Multiple signatures | Yes | No | No | No |
| Different signature for replies | Yes | No | No | No |
| Inherits the web signature | — | Only if mobile signature is off | Only if mobile signature is off | No |
| Stored separately from the others | Yes | Yes | Yes | Yes |
The inherit behaviour reached iOS before Android, so confirm it on your own device and app version by sending yourself a test message.
The practical reading of this table: build your real signature once on the web, then leave every mobile signature field empty. Anything you type into the app replaces a formatted signature with plain text, which is almost never what you want.
Is your signature under Gmail’s 10,000 character limit?
Gmail refuses any signature whose HTML exceeds 10,000 characters, and it counts the markup, not the words you can see. A signature with four visible lines can easily blow past it once tables, inline styles and image code are included. Paste your HTML below to check before Gmail rejects it.
Why the “signature is too long” error appears
The error reads Signature exceeds maximum length of 10000 characters, and it confuses people because the visible text is nowhere near that long. Gmail counts every character of HTML behind the design.
The usual culprit is pasting through Microsoft Word or Google Docs. Both inject enormous amounts of markup — conditional comments, class definitions, redundant style attributes — that can multiply a signature’s real size several times over without changing how it looks. Base64-encoded images are the other frequent cause, because embedding an image directly in the HTML converts it into thousands of characters of text.
| Element | Rough character cost | Notes |
|---|---|---|
| One line of plain text | 40 – 80 | Negligible. Text is almost never the problem. |
| A styled line with inline CSS | 150 – 300 | Font, size and colour declarations repeat on every element. |
| Table wrapper and cells | 300 – 900 | Necessary for reliable layout; worth the space. |
Hosted image (img tag) | 100 – 250 | The efficient way to include a logo. |
| Base64-embedded image | 10,000 – 50,000+ | Blows the entire budget on its own. Avoid completely. |
| Set of six social icons | 2,000 – 5,000 | Each icon carries an image tag plus a wrapping link. |
| Long tracking URL | 200 – 600 each | Query parameters add up fast across several links. |
| Markup pasted from Word | 3,000 – 20,000 | Conditional comments and class definitions you never see. |
Approximate figures for orientation. Paste your own HTML into the checker above for an exact count.
How to bring it back under the limit
- Never paste through a word processor. Copy from the source, or from a signature editor, straight into Gmail.
- Host images at a URL rather than embedding them as base64. An
imgtag pointing at a hosted file costs a hundred characters; the same image encoded inline can cost twenty thousand. - Cut social icons. Six icon images with links can account for more than half of a signature’s markup.
- Shorten long tracking URLs, which often carry hundreds of characters of query parameters.
- Rebuild it clean if all else fails. Delete the signature entirely and retype it in Gmail’s editor to strip out inherited markup.
Adding a logo or image
In the signature editor, place your cursor where the image should sit and select the Insert image icon in the toolbar. Gmail offers Google Drive, a web address, or an upload. Keep the file under roughly 200px wide, and always resize it before uploading rather than relying on Gmail’s small, medium and large options, which scale the display size without reducing the file.
A significant share of recipients have images blocked by default, and Outlook blocks external images in messages from unknown senders. If your logo carries the company name and nothing else does, those recipients see an empty box where your branding should be. Keep every essential detail in text as well.
Using multiple signatures
Gmail lets you create several signatures and assign different ones to new emails and to replies. To switch between them while writing, select the pen icon in the compose window toolbar and pick a signature from the list. This is useful for separating internal and client-facing versions, or for keeping a short one for quick replies.
Formatting Gmail’s signature editor supports
The web editor is more capable than most people realise, but it has hard edges — and what saves in Gmail is not always what arrives in a recipient’s inbox.
| Formatting | In the editor | Caveat when sent |
|---|---|---|
| Bold, italic, underline | Supported | Renders everywhere. Safe. |
| Text colour | Supported | Safe, but set link colours deliberately or Outlook overrides them. |
| Font family | Six choices | Only web-safe faces. Anything else substitutes on the recipient’s machine. |
| Font size | Four presets | Small, Normal, Large, Huge only. No pixel control in the editor. |
| Hyperlinks | Supported | Safe. Use descriptive text rather than a bare URL. |
| Images | Supported | Blocked by default for many recipients. Never let one carry key information. |
| Bulleted lists | Supported | Renders, but rarely suits a signature. |
| Tables | Not in the editor | Paste table-based HTML in instead; Gmail preserves it. |
| Custom HTML entry | No source view | No code editor. Paste rendered HTML from elsewhere. |
| Background colours | Not offered | Only achievable by pasting HTML with inline cell backgrounds. |
Gmail has no HTML source view, which trips up anyone with existing signature code. The way in is to render your HTML in a browser first, select the rendered result, copy it, and paste that into the editor. Gmail keeps the underlying markup — including tables, which the toolbar cannot create.
Troubleshooting
| Symptom | Likely cause | Fix |
|---|---|---|
| No signature on any message | Signature created but never assigned | Set it under Signature defaults for both new emails and replies, then Save Changes |
| Shows on new mail, not replies | The replies dropdown is separate and still on “No signature” | Set the second dropdown under Signature defaults |
| Will not save at all | Over the 10,000 character limit | Check the count above, then strip Word markup and base64 images |
| Nothing on the phone | Mobile signature is separate from desktop | Turn the mobile signature off to inherit the desktop one, or set a plain-text one in the app |
| Logo missing for recipients | Images blocked, or hosted somewhere private | Host on a public URL and keep all key details in text too |
| Buried under quoted replies | “Insert signature before quoted text” is unticked | Tick that box in the Signature section |
| Formatting looks wrong | Pasted through Word or Docs | Rebuild it in Gmail’s editor or paste from clean source HTML |
| Cut off mid-way in the inbox | Whole message exceeded Gmail’s clipping threshold | Shorten the message; the signature hides behind “show trimmed content” |
Need a signature to paste in?
Sixteen free templates built for Gmail and Outlook — table markup, inline styles, no images to break, and every one measured live so you can see it fits a phone screen before you copy it. All sit far below the 10,000 character limit.
Setting signatures for a whole team
Everything above configures one mailbox. Across an organisation the manual approach breaks down quickly.
Google Workspace has no built-in way for an administrator to set signatures centrally through the admin console for every user. Doing it by hand means each person pasting the template themselves, each phone configured separately, and no way to correct a wrong job title or swap a campaign line without asking everyone again. Signatures drift apart within weeks.
Server-side signature tools solve this by appending the signature at the mail server as messages leave, rather than in each client. One template applies to everyone, details populate from your directory, and it works identically on desktop, web and mobile — which also sidesteps the plain-text mobile limitation entirely, since the phone never handles the signature at all.
Compare centralised signature management tools for Google Workspace and Microsoft 365.
Questions
Where is the signature setting in Gmail?
Select the gear icon in the top right of Gmail, choose See all settings, stay on the General tab, and scroll down to the Signature section. It sits well down the page, below the language, maximum page size, undo send and stars settings. On mobile it is in a different place entirely: the three-line menu, then Settings, then your account, then Mobile Signature.
Why is my Gmail signature not showing up?
The most common cause is that the signature was created but never assigned. Creating one does not switch it on — you also have to select it under Signature defaults, which has two separate dropdowns for new emails and for replies and forwards. Both start on “No signature”.
If it shows on new messages but not replies, only the first dropdown was set. If it saves but never appears at all, check you scrolled to the bottom and selected Save Changes.
Why can’t I add an image to my signature in the Gmail app?
The mobile app’s Mobile Signature field accepts plain text only. It has no formatting toolbar, no image insertion, and strips bold, colours and clickable links. This is a limitation of the app, not something you can work around inside it.
The practical answer is to leave the mobile signature switched off. The app then applies the formatted signature you set on the web, images included. A mobile signature, once set, takes precedence over the desktop one — so removing it is what lets the good version through.
What is the character limit for a Gmail signature?
10,000 characters, and Gmail counts the underlying HTML rather than the visible words. Tables, inline styles, link markup and especially base64-encoded images all count toward it, which is why a signature with four short lines can still be rejected. Exceeding it produces the error “Signature exceeds maximum length of 10000 characters” and the signature will not save. Use the counter on this page to check before you paste.
Can I have different signatures for different email addresses?
Yes. If you have send-as addresses or aliases configured, a dropdown appears above the signature editor letting you pick which address you are editing the signature for. Each address keeps its own set. Separate Gmail accounts are entirely independent and need configuring one at a time.
How do I remove or change my Gmail signature?
To change it, edit the text in the same Signature section and select Save Changes. To stop it appearing without deleting it, set both Signature defaults dropdowns back to “No signature”. To delete it outright, hover over the signature name in the left-hand list and select the bin icon. On mobile, clear the Mobile Signature text field or switch the toggle off.
Does my Gmail signature appear in the Gmail mobile app automatically?
Only if no mobile signature is set. The two are stored separately, and whatever sits in the app’s Mobile Signature field wins. Clear it and the app uses your web signature instead. This behaviour arrived on iOS before Android, so test it by sending yourself a message from the app rather than assuming.
Can an administrator set Gmail signatures for everyone in the company?
Not through the Google Workspace admin console directly — there is no built-in central signature control for all users. Organisations that need consistency use a third-party signature management tool that applies signatures at the mail server as messages are sent. That approach also covers mobile, since the signature is added after the message leaves the device.
Edvard Smith
Email signature & migration specialistWrites about email signature deployment and mailbox migration at EmailSignatureHelp. Every step in this guide was walked through in Gmail on the web, the Gmail Android app and the Gmail iOS app in July 2026 rather than copied from Google’s documentation, which is why the mobile inheritance behaviour and the Signature defaults trap appear here and rarely elsewhere.