You send an email from your computer - the signature looks neat, with name, title, and phone number. You send the same email from your phone - the signature is either missing entirely, or says "Sent from my iPhone".

This is a small thing clients rarely notice consciously, but they feel it - it comes across as inconsistent, like the business isn't fully organized. The good news is it gets fixed once, on each device, and then you never have to think about it again.

Why the signature doesn't carry over automatically

The signature isn't part of the email account on the server - it's a setting inside each individual app you use to send mail. That means if you check email on your phone, computer, and webmail, the signature needs to be entered three times, separately, once in each app.

How to set up a signature in Outlook (desktop version)

1. Open Outlook, go to File > Options > Mail.
2. Click the Signatures button.
3. Click New to create a new signature, and give it a name (e.g. "Business signature").
4. Enter the signature text - name, title, business name, phone number, and optionally a company logo as an image.
5. In the dropdown menus on the right, select this signature as the default for New messages and for Replies/forwards.
6. Click OK to save.

How to set up a signature in new Outlook or Outlook on the web

1. Open Outlook (the new version, or outlook.office.com) and click the gear icon for Settings.
2. Look for Mail > Compose and reply.
3. Enter your signature text in the provided field.
4. Turn on the options for the signature to be automatically added to new messages and replies.
5. Save your changes.

How to set up a signature on Android

1. Open the Gmail app, tap the three lines in the top left corner, then Settings.
2. Select your email account from the list.
3. Look for the Mobile Signature option.
4. Enter your signature text - on mobile, it's best to keep it shorter than on a computer, no images or logo, just the basic details.
5. Save your changes.

How to set up a signature on iPhone

1. Open Settings on the phone.
2. Scroll down to Mail, then select Signature.
3. If you have multiple email accounts, choose Per Account so each account has its own signature, or All Accounts for the same signature everywhere.
4. Delete the default text "Sent from my iPhone" and enter your signature.

Important note: the iPhone signature only supports plain text, with no way to add an image or logo directly through this option - that's a limitation of the iOS app itself, not something you can work around from settings.

How to set up a signature on a Mac

1. Open the Mail app, go to Mail in the top menu > Preferences (or Settings) > Signatures.
2. Click the plus (+) to add a new signature.
3. Enter your text, and, if you want, drag an image (logo) directly into the signature field.
4. On the right side, link the signature to the appropriate email account.

How to set up a signature in Thunderbird

1. Go to Tools > Account Settings.
2. Select your email account on the left.
3. Find the Signature text field and enter your signature - for a formatted signature with an image, turn on the HTML option next to it.
4. Save your changes by closing the settings window.

Why images and logos don't always work in a signature

This is a common source of frustration - a signature with a logo looks great on a computer, and on a phone the logo simply isn't there.

• Some mobile apps (like the basic iOS Mail setting) don't support images in signatures at all, only plain text
• Even when the image works, some recipients have images automatically blocked in emails, so instead of the logo they see blank space or a "broken image" icon
• Because of this, a practical approach is to use your main, formatted signature with a logo on the computer (Outlook, Mac Mail, Thunderbird), and a simple, text-only signature (name, title, phone, email) on the phone

What a good business signature should include

• First and last name
• Title or position at the business
• Business name
• Phone number
• Link to the website (optional)
• Company logo (optional, only where it displays reliably)

Avoid overcomplicated signatures with too many links, quotes, or large images - they feel chaotic and load more slowly, especially on mobile networks.

Frequently asked questions

Can I set up the signature once and have it apply everywhere automatically? No - as described, each app (Outlook, Gmail app, iPhone Mail, Mac Mail, Thunderbird) has its own, separate signature setting. It needs to be entered in each one individually.

Why does my logo look stretched or out of proportion in the signature? Usually because the original image is too large or has the wrong proportions - it's best to prepare the logo in a smaller, correct size beforehand (say, around 150-200 pixels wide) before inserting it into the signature.

Should every employee have an identical signature? It's recommended that the format be the same (layout, colors, font), with only the personal details differing (name, title, direct phone number) - that builds a consistent impression of the business.

Does the signature slow down sending an email? Not noticeably, unless it contains a very large image - in that case, it's worth shrinking the image file size before adding it to the signature.

In closing

Setting up your signature on every device takes about ten minutes total, but it's only done once - after that, every email you send, from any device, looks professional and consistent.

If you're currently sending mail with no signature, or with the default "Sent from my iPhone", that's one of the fastest things you can fix today.