How to Change Your Signature Line in Outlook

Email signatures do a lot of quiet work — they introduce you, reinforce your brand, provide contact details, and set the tone for every message you send. Whether you're updating a job title, switching companies, or simply cleaning up a cluttered sign-off, knowing how to change your signature line in Outlook is a practical skill worth getting right.

The process varies more than most people expect, depending on which version of Outlook you're using and on which device.

What Is an Outlook Signature Line?

In Outlook, a signature is a block of text (and optionally images or links) that gets appended to your emails automatically or manually. A signature line typically refers to the closing line itself — your name, title, phone number, or any combination of those elements.

Outlook lets you create multiple signatures and assign different ones to:

• New emails you compose
• Replies and forwards
• Specific email accounts (if you manage more than one inbox)

This flexibility is useful, but it also means there are several places where a signature can be set — and several places where a change needs to happen if something looks wrong.

How to Change Your Signature in Outlook on Windows (Desktop App)

This applies to Outlook for Microsoft 365, Outlook 2021, 2019, and 2016 on a Windows PC.

1. Open Outlook and select File from the top menu
2. Click Options, then choose Mail from the left-hand panel
3. Click the Signatures… button — this opens the Signatures and Stationery dialog
4. Under Select signature to edit, choose the signature you want to modify
5. Edit the text in the editing box below — you can change font, size, color, and add links or images using the formatting toolbar
6. Under Choose default signature, confirm which account and which email type (new messages vs. replies) this signature applies to
7. Click OK to save

✏️ If you have multiple signatures set up, make sure you're editing the correct one. It's easy to update a signature that isn't actually assigned to outgoing mail.

How to Change Your Signature in Outlook on Mac

The Outlook for Mac interface differs from the Windows version:

1. Open Outlook and go to Outlook in the menu bar, then click Preferences
2. Select Signatures
3. In the left panel, click the signature you want to edit
4. Modify the text in the editing panel on the right
5. Changes save automatically — there's no separate save button

On Mac, you can also drag and reorder signatures, and assign a default per account from the same preferences panel.

How to Change Your Signature in Outlook on the Web (OWA)

Outlook on the Web (sometimes called OWA or accessed via outlook.com or your organization's Microsoft 365 portal) has its own signature settings — separate from the desktop app.

1. Click the Settings gear icon in the upper-right corner
2. Click View all Outlook settings at the bottom of the panel
3. Go to Mail → Compose and reply
4. Edit your signature in the text box under Email signature
5. Toggle whether to automatically include it in new messages and/or replies
6. Click Save

⚠️ Changes made in Outlook on the Web do not sync to the desktop app, and vice versa. If you use both, you'll need to update your signature in each place separately.

How to Change Your Signature in Outlook on Mobile (iOS and Android)

The Outlook mobile app has a simplified signature setting:

1. Tap your profile icon in the top-left corner
2. Tap the gear icon (Settings) at the bottom
3. Scroll down to find Signature
4. Edit the text field and tap the checkmark or Done to save

Mobile signatures in the Outlook app are plain text only — no rich formatting, images, or HTML. This is a significant limitation compared to the desktop or web versions.

Comparing Signature Options Across Outlook Versions

Common Reasons a Signature Change Doesn't Stick

If you've edited your signature but it's not showing up correctly, a few things are worth checking:

• You edited the wrong platform — desktop and web signatures are stored independently
• Default assignment wasn't updated — the new or edited signature may not be set as the default for new messages or replies
• Your IT or admin policy overrides it — in corporate environments, Exchange or Microsoft 365 administrators can enforce server-side signatures that append regardless of personal settings
• You're replying in plain text mode — some Outlook configurations strip HTML signatures when replying in plain text format

Variables That Shape Your Experience 🔧

How straightforward this process is depends on several factors specific to your situation:

• Your Outlook version — Microsoft 365 subscribers get the most current interface; older perpetual licenses (2016, 2019) may look slightly different
• Whether you're on a managed device — corporate IT policies can restrict or override signature settings entirely
• How many email accounts you manage — multiple accounts in one Outlook profile require separate signature assignments for each
• Whether you need HTML formatting — if your signature includes a logo, styled font, or clickable links, the desktop app gives you the most control; mobile is far more limited
• Whether your org uses server-side signatures — some businesses apply branded signatures at the email server level, meaning personal Outlook settings may be partially or fully overridden

The right approach to changing your signature line ultimately comes down to where you're sending mail from, what your signature needs to contain, and how much control your account setup actually gives you.