Gmail signature on iPhone and Android: why it differs from the web, and how to fix it

The short answer

Gmail on the web stores a rich signature: logo, colours, links, a banner. The Gmail app on iPhone and Android has its own setting called Mobile signature, and it is plain text. If a person types anything into it, every email they send from the app ends with that text instead of the web signature. If they leave it empty, Google says the app uses the signature set up on the computer.

So the logo does not disappear because the app cannot show it. It disappears because someone, at some point, typed a mobile signature, often years ago, often just their name. The fix for one person is to clear that field. The fix for a company is to stop relying on each person’s phone settings at all, which is the last section of this article.

Two signatures, two places

Gmail keeps the web signature in your account. It is the one you edit at Settings → See all settings → Signature in a browser, and the one Google Workspace tools write through the Gmail API. It can hold formatted text, images and links, and you can have several and choose one per message.

The Gmail app keeps the mobile signature on the device, per account. On Android it is at Menu → Settings → your account → Mobile signature. On iPhone and iPad it is at Settings → Compose and Reply → Signature settings, with a Mobile Signature switch. Google describes both as text. There is no formatting toolbar and no way to add an image.

The two do not sync. A person with a phone and a tablet can have three different signatures: the web one, the phone one and the tablet one. Nothing in the Admin console shows which is in use.

Why the phone signature goes wrong at a company

Three patterns account for almost every complaint we hear about signatures from phones.

The old mobile signature. Somebody set up their phone in 2019, typed “Sent from my phone” or their name, and forgot. Four years and two job titles later, every email they send from the phone still ends with it. The web signature IT rolled out last month never appears on that device, and the person does not notice because they see their own emails rarely.

The signature that was never set at all. A new hire gets a laptop and a phone on the same day. IT puts a signature on the web account; the phone is fine, because an empty mobile signature falls back to the web one. Then the person reads a tip, sets a mobile signature to “look professional”, and from that day the company signature is gone on mobile.

The reply that carries no signature. On the web, Gmail’s signature setting has an option to insert the signature before quoted text in replies. The app has no such option; whether a signature appears on a reply from the phone depends on which signature is in use and how the thread is quoted. Marketing sees a banner on new emails and nothing on replies and assumes the tool is broken.

None of these is a bug. They are three people’s devices doing exactly what three people once told them to do.

The fix for one person

If you only need your own phone to match your web signature, clear the mobile signature and let the fallback do its job.

Android

1. Open the Gmail app and tap the menu at the top left.
2. Scroll down and tap Settings, then your account.
3. Tap Mobile signature.
4. Delete everything in the box and tap OK. Leave it empty; do not type a space.

iPhone and iPad

1. Open the Gmail app and tap the menu at the top left.
2. Tap Settings, then under Compose and Reply tap Signature settings.
3. Turn Mobile Signature off.
4. Tap Back to save.

Send yourself a test email from the app. It should now carry the web signature, logo and all. If it still shows plain text, you have a second device or a second account on the same phone with its own mobile signature; repeat for each.

One limit to know: the Gmail app on a phone renders the web signature as Gmail renders it, so an image stored on a server you control loads fine, but an image pasted in from a desktop clipboard can show as a broken square on some devices. Signature tools host the logo for that reason.

The fix for a company: four ways

Clearing a field on 80 phones is not a plan. These are the four ways an organisation gets one signature on the web and on phones, and what each one actually does.

1. Ask everyone to clear the mobile signature

Send the steps above to the company. It works for about a third of people on the first ask, and nothing stops anyone setting a mobile signature again the next week. Useful as a one-off, useless as a policy.

2. The Admin console footer

Google Workspace admins can append a footer to every outgoing message from the Admin console (Apps → Google Workspace → Gmail → Compliance → Append footer). Because it is added on Google’s servers after the message is sent, it appears on mail from phones too, and no phone setting can remove it. The cost is that it is one fixed block of text per organizational unit: no name, no title, no phone number for the sender, nothing visible while they write, and it sits under every quoted reply in a thread. Fine for a legal line; not a signature.

3. A script against the Gmail API

The Gmail API lets an admin set the web signature for every user through domain-wide delegation, usually with GAM. That gets a real, personal signature onto every account in one run. It does nothing about mobile signatures, because those live on the device, not in the account. People who have one keep it. The script also has to be rerun whenever a title changes, and someone has to own it. We cover the GAM route step by step in the guide to setting a signature for all users.

4. A signature tool that writes into Gmail

A tool like Signifier does what the script does, continuously: it fills one template from the directory and writes each person’s web signature through the Gmail API, then rewrites it when the directory or the template changes. The mobile signature question is the same as with the script: the app falls back to the web signature when the mobile one is empty, so the tool’s signature shows on phones for everyone who has not set one. What a tool adds over the script is that it tells you who has. Signifier’s people list shows, per person, whether the signature it wrote is what Gmail is sending, so the two or three people with an old mobile signature are a short list, not a company-wide email.

What recipients see on their phones

The other half of “mobile” is the reader. Most of the people your company emails will open it on a phone, in the Gmail app, Apple Mail or Outlook, often in dark mode.

• Width. A signature laid out as a 600-pixel table gets scaled down on a phone until the text is unreadable, or wraps into a mess. Keep the signature under about 320 pixels wide, or use a single column.
• Dark mode. Gmail and Apple Mail invert or darken backgrounds. A black logo on a transparent background disappears; a dark-blue text colour becomes unreadable on a near-black ground. Test the signature in dark mode on a phone before publishing it to anyone.
• Images. Some mail apps, and many corporate Outlook setups, hold remote images until the reader allows them. Put the name, title and number in text, never in an image, so the signature says who you are even when the logo is a grey box.
• Links. Phone numbers written as text become tappable on most phones. A “Book a call” link is more useful on a phone than on a desktop; a wide banner is less.

Signifier previews every signature in Gmail, Outlook and Apple Mail, in light and dark mode, before it is published, which is the cheapest time to find out that the logo vanishes.

A checklist for IT

1. Decide what must be on every message from every device (a legal line, say) and put that, and only that, in the Admin console footer.
2. Put the real signature in the web signature of every account, with a script or a tool, filled from the directory.
3. Tell people once, in writing, that the mobile signature should be empty, with the four taps above for each platform.
4. Find the people who still have one. With a tool, read the list; without one, ask managers to check their own teams’ sent mail from phones.
5. Keep the signature under 320 pixels wide, name and title in text, and look at it in dark mode on a phone before publishing.
6. Re-check after each new-starter batch; new phones are where mobile signatures get set.