How to Add an Email Signature in Apple Mail on Mac and iPhone

The short answer: what works on each device

Apple Mail keeps two separate signature settings. The Mac version lives in the Mail app and can hold formatted text, colours, lists, images and your contact card. The iPhone version lives in the iOS Settings app and holds plain text only. Apple's own iPhone guide says that you can only use text in Mail signatures on that device. So the signature you build on a Mac will not reach the iPhone in its designed form, and you will need to rebuild a plain-text version for the phone.

This matters most for employees and HR teams who want every outgoing message to carry the same look. A logo, a styled name line or a clickable website address will appear on the Mac, but not on the phone. Plan for two versions from the start: one rich version for desktop and one plain version for mobile.

No law or regulation sets how an email signature must look. The rules here are set by Apple's software, so the official source is Apple's own support documentation. If your signature carries legal wording, such as a confidentiality notice required by your company's policy, that wording is a business decision and should be checked with your legal adviser, not taken from a setup guide.

Set up the signature on a Mac, step by step

Open the Mail app on your Mac. Choose Mail > Settings from the menu bar, then click Signatures. The window has three columns. The left column lists your accounts, the middle column lists the signatures for the selected account, and the right column is the preview where you type.

1. Select the email account in the left column. If you create a signature while All Signatures is selected, you must drag it onto an account before you can use it.

2. Click the add button below the middle column and give the signature a name. The name is what you will see later in the Signature menu when you write a message.

3. In the right-hand preview, type your text. Use the Format menu to change the font, colour, alignment and lists. Use the Edit menu to turn text into links and to check spelling.

4. To add a logo, drag an image file into the preview area. To add your contact details quickly, drag your card from the Contacts app into the same area.

5. Choose the signature from the Choose Signature menu for that account, so that it is added to new messages automatically. Apple's guide also describes options to alternate between several signatures on an account, at random or in sequence.

6. Decide where the signature sits in a reply. The option "Place signature above quoted text" controls this. Deselect it if you want your signature to follow the original message when you reply or forward.

Apple's documentation says that if you use iCloud Drive with Mail turned on, your signatures are available on other Macs that also use iCloud Drive. Your iPhone is not one of those Macs, so set it up separately.

The font checkbox that can strip your formatting

Each Mac signature has a checkbox called Always match my default message font. Apple describes it as making the selected signature use the message font set in the Fonts & Colours settings. In practice, many people report that the checkbox overrides the font and size you set in the signature, so the signature looks plain or the wrong size.

A long-running Apple Community thread argues that the checkbox removes font information from the signature itself, and that the font change only affects what the sender sees on screen. That view is a user's reading of the behaviour, not an official Apple statement, so test it yourself. The practical rule is simple. If you want your signature to keep its own fonts, sizes and colours, leave the checkbox unticked, then style the signature text directly.

Here is the test. Create the signature, leave the checkbox in the state you want, and send a message with the signature to a second address you can open on another device. Check the font size, the colour and the spacing in the received copy. Then change the default message font in the Fonts & Colours settings, send a second test, and compare the two. If the signature shifts with the default font, the checkbox is active.

Set up the signature on an iPhone, step by step

Apple's iPhone guide gives the path. Open the Settings app, tap Apps, then tap Mail, then tap Signature, which sits below the Composing heading. On an iPhone running an earlier version of iOS, the Apps step may not appear, so tap Mail directly from the Settings list.

1. Tap the text field and delete the default line that the phone adds to outgoing messages.

2. Type your name, job title, company, and a phone number. Keep the text short, with one item per line.

3. If you have more than one email account, tap Per Account. This lets each account carry its own signature. If you choose the all-accounts option, one signature applies everywhere on the phone.

4. Close Settings, open Mail, and start a new message to check that the signature appears at the bottom.

Text only means text only. You cannot add a logo, a photo or a clickable link to the signature field. If you paste rich text from a Mac or a web page, the phone may keep some of the styling, but this is not a dependable design and you should not rely on it. Apple's own description limits the field to text. If the design of your signature matters to your brand or to a regulator, the iPhone version will look different from the Mac version, and you should accept that or manage it with your IT team.

Worked example: one person, three accounts, two devices

Take an operations manager at a logistics firm in Pune who uses three accounts: a work account, a personal account and a shared operations account. She also reads mail on a Mac at the office and on an iPhone on the road. The firm's brand guide asks for a name, title, phone number and company logo on every work message.

The arithmetic is simple. She needs one rich signature for the Mac and one plain signature for the iPhone. The work account needs both versions. The shared account needs the same two versions. That gives two signatures per account for the two devices she uses, so 2 x 2 = 4 signature entries across the accounts she uses for work. The personal account can keep one plain signature for both devices, which adds 1 entry on each device. In total, she sets up and checks 6 signature entries across two devices.

Her routine is to check each entry after any change to the logo or phone number. The numbers only come from her own setup. They are not a benchmark. A person with one account and one device faces a far smaller job.

Cases that change the answer

The right setup depends on how you use the email, not only on the device.

Two cases need a different approach. The first is a mail account managed by your employer, such as a work account on a company mobile device managed by an administrator. In that case, the signature may be set by policy rather than by you, and you should check with your IT team before changing it. The second is a signature that must carry a regulated disclosure. A typical setup guide cannot tell you what the disclosure must say, so the wording is for your legal adviser.

Common mistakes

• Designing a rich signature on a Mac and assuming it will appear on the phone. It will not keep its design on the iPhone.
• Leaving the font checkbox ticked and then wondering why the signature shows the default font.
• Pasting a long signature with a large logo into the iPhone field. The field accepts text, so the logo will not appear and the text may look cluttered.
• Setting All Accounts on a phone that carries a work account and a personal account, so that personal mail carries a work title.
• Forgetting to remove the default line that the phone adds to outgoing mail.
• Testing only with one recipient. Send the test to a second provider, such as a personal webmail address, because some mail apps display the same signature differently.

What to check with IT or HR

Some decisions should not be made on the device alone. Check these points with your IT team or HR before you roll out a standard signature to staff.

First, confirm whether the company has a brand template for signatures and who owns it. Second, confirm whether any signature must carry a disclaimer, a registration number or a privacy notice, and who approves the wording. Third, confirm which devices are managed by the company, because managed devices may block changes or reset them. Fourth, ask whether staff should keep a plain text copy of the signature for the phone and a rich copy for the desktop, and who keeps both up to date.

Where a disclaimer or privacy notice is required by law in your country, the source is the official text of that law and the regulator's guidance, not the device setting. This explains the setup in general terms; it is not legal or tax advice for your case.

How employers take routine HR and payroll work off staff

Many businesses find that signature updates, staff contact changes and new-starter email set-up eat time in HR and payroll teams. AiStaffo builds AI workers that take over routine business work, such as data entry, follow-ups, reconciliations, reports and documents, and offers free tools that help owners, HR and finance teams do that work faster. A typical setup connects the staff list to the document flow, so that a change of title or phone number updates the approved signature text automatically, and a person checks the result before it goes out. The results depend on your own numbers, which the free audit measures. Book a free automation audit.