How to Create a Signature in Outlook 365

Email signatures do more than add your name to the bottom of a message. They establish professionalism, deliver contact details consistently, and — in many business environments — communicate branding or legal disclaimers automatically. Outlook 365 gives you a flexible signature system, but the setup process has a few moving parts worth understanding before you dive in.

What an Outlook 365 Signature Actually Does

A signature in Outlook 365 is a block of text, images, or formatted content that gets appended to your emails automatically or on demand. You can create multiple signatures — one for new emails, another for replies and forwards — and assign different signatures to different email accounts if you manage more than one.

Signatures are stored per device and per application. This is an important distinction: a signature you create in the Outlook desktop app on your Windows PC will not automatically appear in Outlook on the web (OWA) or on your mobile device. Each environment has its own signature settings.

Creating a Signature in the Outlook 365 Desktop App (Windows)

This is the most common starting point for business users.

1. Open Outlook and select File → Options
2. In the left panel, click Mail
3. Under the Compose messages section, click Signatures…
4. In the Signatures and Stationery dialog, click New
5. Give your signature a name (e.g., "Work — Full" or "Replies — Short")
6. Use the editor panel to compose your signature — you can format text, adjust font size, add hyperlinks, and insert images
7. Under Choose default signature, assign the signature to an email account and select when it appears: New messages and/or Replies/forwards
8. Click OK to save

The built-in editor supports basic rich text formatting. If you want something more visually complex — like an HTML signature with aligned logos and social icons — you may need to create it externally and paste the HTML in, or use a third-party signature management tool.

Creating a Signature in Outlook on the Web (OWA)

If you use Outlook through a browser at outlook.office.com or outlook.office365.com, the signature setup is separate from the desktop app.

1. Click the gear icon (Settings) in the top-right corner
2. Select View all Outlook settings at the bottom of the panel
3. Navigate to Mail → Compose and reply
4. Scroll to the Email signature section
5. Type and format your signature in the editor
6. Toggle options to automatically include it in new messages and/or replies and forwards
7. Click Save

OWA's signature editor is simpler than the desktop version. It supports basic formatting and image insertion, but complex HTML layouts may not render as expected.

Creating a Signature in Outlook Mobile (iOS/Android)

The Outlook mobile app has its own signature setting, and by default it shows "Get Outlook for iOS" or a similar placeholder.

1. Tap your profile icon in the top-left corner
2. Go to Settings (gear icon)
3. Select your email account
4. Tap Signature
5. Replace or edit the existing text with your preferred signature
6. Tap the back arrow to save

📱 Mobile signatures are plain text only in the native Outlook app — no rich formatting, images, or HTML. If formatted signatures on mobile matter to you, that's a constraint worth factoring into your workflow.

Key Variables That Affect Your Signature Setup

Not every user has the same situation, and several factors shape what your signature experience actually looks like:

When Company Policy Overrides Your Personal Settings

In many business Microsoft 365 tenants, IT administrators can deploy organization-wide email signatures through the Exchange admin center or third-party tools like CodeTwo or Exclaimer. These append signatures at the mail server level, meaning they appear regardless of what any individual user sets locally.

If you work in a managed environment and your personal signature isn't appearing — or a different one is being added automatically — it's likely a policy decision rather than a settings error. ✉️

The Plain Text vs. HTML Distinction

Outlook 365 supports three email formats: HTML, Rich Text, and Plain Text. Your signature behaves differently depending on which format you compose in.

• HTML format supports full formatting, images, and clickable links in signatures
• Rich Text supports some formatting but can cause rendering issues for non-Outlook recipients
• Plain Text strips all formatting — your signature will appear as unformatted characters only

Most modern business email is sent in HTML format, which is why HTML signatures are the default expectation. But if your organization or a specific contact requires plain text, you'll need a plain text version of your signature ready.

Signatures Across Multiple Accounts

If you have more than one email address connected to Outlook 365 — say, a primary work account and a shared mailbox — you can create separate signatures and assign each to the appropriate account. In the Signatures and Stationery dialog on desktop, the dropdown under Choose default signature lets you control this per account.

This matters if your different accounts carry different roles: a personal signature for your primary address and a more formal one for a team or department mailbox, for instance.

What Determines the Right Setup for You 🖥️

The mechanics of creating a signature in Outlook 365 are straightforward, but the right configuration depends on how many accounts you manage, which devices you send from regularly, whether your organization enforces any signature policies, and how important visual formatting is in your communications. Someone sending emails from a single account on one device has a simple path. Someone managing multiple accounts across desktop, web, and mobile — with branding requirements — is navigating a meaningfully different set of decisions. Your own mix of those factors is what ultimately shapes which approach makes sense.