How to Add a Signature in Outlook (Desktop, Web & Mobile)

An email signature does more than sign off a message — it carries your name, title, contact details, and sometimes a professional brand image every time you hit send. Outlook supports signatures across all its versions, but the setup process and available options vary depending on which version you're using and how your account is configured.

What Is an Outlook Signature?

A signature in Outlook is a block of text (and optionally images or links) automatically appended to outgoing emails. You can create multiple signatures — one for new emails, another for replies — and assign different signatures to different email accounts if you manage more than one.

Signatures can include:

• Your name, job title, and company
• Phone numbers and website URLs
• A logo or headshot image
• Social media links
• Legal disclaimers (common in corporate environments)

How to Add a Signature in Outlook Desktop (Windows)

This applies to Outlook for Microsoft 365, Outlook 2019, Outlook 2016, and similar versions.

1. Open Outlook and click File → Options
2. Select Mail from the left panel
3. Click Signatures… under the "Compose messages" section
4. In the Signatures and Stationery window, click New
5. Name your signature (e.g., "Work," "Personal")
6. In the editing box below, type and format your signature
7. Under Choose default signature, assign it to an email account and select when it appears — for New messages and/or Replies/forwards
8. Click OK to save

The formatting toolbar in the signature editor supports font styling, colors, hyperlinks, and image insertion — giving you meaningful control over how it looks.

How to Add a Signature in Outlook on Mac

The Mac version of Outlook has a slightly different path:

1. Open Outlook → click Outlook in the menu bar → Preferences
2. Select Signatures
3. Click the + button to create a new signature
4. Name it, then type your signature content in the editor panel
5. Use the gear icon or dropdown to set it as default for an account

⚠️ One key difference: the Mac version's signature editor is more limited in formatting compared to the Windows version. Complex HTML signatures may not render as expected unless inserted via another method.

How to Add a Signature in Outlook Web (OWA)

Outlook on the web (outlook.com or your organization's webmail) has its own signature settings that are separate from desktop Outlook — changes in one don't automatically carry over to the other.

1. Log in to Outlook Web
2. Click the Settings gear icon (top right)
3. Select View all Outlook settings at the bottom of the panel
4. Go to Mail → Compose and reply
5. Under Email signature, type and format your signature
6. Toggle on Automatically include my signature on new messages and/or replies
7. Click Save

The web editor supports basic rich text formatting, image embedding, and hyperlinks.

How to Add a Signature in Outlook Mobile (iOS & Android)

The Outlook mobile app handles signatures differently — it's simpler and text-only by default.

1. Open the Outlook app
2. Tap your profile icon (top left) → Settings (gear icon)
3. Select your email account
4. Tap Signature
5. Edit or replace the default text

📱 Mobile signatures are plain text only — no images, no HTML formatting. If you need a rich signature on mobile emails, this is a genuine limitation of the app.

Comparing Signature Options Across Outlook Versions

Variables That Affect Your Signature Setup 🔧

A few factors determine how your signature behaves and what's possible:

Your Outlook version matters significantly. Microsoft 365 subscribers get the most current feature set. Older perpetual licenses (Outlook 2016, 2019) may lack some newer formatting options.

Account type plays a role too. Exchange and Microsoft 365 accounts managed by an IT department may have organization-level signature rules set via server-side policies — meaning your personal signature settings could be overridden or appended automatically by an admin.

HTML vs. plain text email format affects rendering. If you compose emails in plain text mode, even a richly formatted signature will strip down to plain text. Outlook's default compose format (found under File → Options → Mail → Compose messages in this format) controls this behavior.

Cross-client compatibility is another variable. A signature that looks perfect in Outlook desktop may render differently in Gmail, Apple Mail, or another recipient's email client — particularly if it uses custom fonts or embedded images.

When Signatures Don't Appear Automatically

If your signature isn't showing up automatically, common reasons include:

• The signature wasn't assigned to the correct account or message type (new vs. reply)
• You're composing in a different Outlook profile than where the signature was created
• An IT admin has disabled or overridden personal signature settings
• You're using a different Outlook client (web vs. desktop) that has separate settings

Whether a simple text block or a fully branded HTML design is right for your situation depends on the accounts you manage, the devices you use, and whether your setup is personal or governed by organizational policies — factors that look different for every user.