How to Set Up an Email Signature in Outlook

Setting up a signature in Outlook from scratch requires two steps most guides skip: confirming Outlook is in HTML compose mode (required for formatted signatures), and assigning the signature per email account. This guide covers full setup including multi-account configuration and technical HTML requirements.

Updated: March 2026·~5 min read·Works with: Outlook 2016, 2019, 2021, 365

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Step 1: Confirm Outlook is in HTML Mode

This is the most commonly missed step. If Outlook composes in Plain Text or Rich Text format, HTML signatures will not display correctly — they'll appear as raw text or stripped of all formatting.

Open Outlook Options

Click File → Options.

Go to Mail Settings

Click Mail in the left sidebar.

Set Format to HTML

Under Compose messages, find the dropdown for “Compose messages in this format”. Set it to HTML.

Click OK

Click OK to save this setting.

Step 2: Create Your Signature

Open Signature Settings

File → Options → Mail → click Signatures…

Click New

Click the New button. Enter a name (internal label, e.g. “Main” or your name). Click OK.

Paste Your Signature Content

Click in the large editing area at the bottom. Paste your signature with Ctrl+V. If using a SignForge signature, the table layout and inline styles paste correctly and will render in Outlook.

Step 3: Assign Defaults Per Email Account

Outlook supports a different default signature for each email account and for new messages vs. replies/forwards. This is configured in the “Choose default signature” section of the Signatures dialog.

Select Your Email Account

In the E-mail account dropdown under “Choose default signature”, select your primary email account.

Set Signature for New Messages

In the New messages dropdown, select your signature.

Set Signature for Replies/Forwards

In the Replies/forwards dropdown, select your signature (or a shorter version — many people use a minimal text-only signature for replies to reduce thread clutter).

Repeat for Additional Accounts

If you have multiple email accounts configured in Outlook, select each one from the E-mail account dropdown and assign signatures individually. Each account stores its own defaults.

Save and Close

Click OK.

Step 4: Test Your Setup

✓

Open a new compose window

Your signature should appear automatically. If it doesn't, recheck the default assignment in Step 3.

✓

Send a test email to a Gmail address

Gmail renders HTML signatures differently from Outlook. This confirms images load, links work, and layout holds cross-client.

✓

Open the test on mobile

View the received email on a phone. Signatures wider than 600px cause horizontal scrolling. If it overflows, your signature table is too wide.

✓

Reply to a thread

Check that your reply signature (if different from the new message signature) appears as expected in reply mode.

Outlook HTML Signature Requirements

Outlook uses the Microsoft Word HTML rendering engine. These technical constraints apply to all signatures in Outlook 2016 through Microsoft 365 (classic):

Tables only — no flexbox or CSS grid

Multi-column layouts must use HTML <table> elements. Add border="0" cellpadding="0" cellspacing="0" to every table.

Inline CSS only

Outlook ignores <style> blocks and CSS class selectors. All styles must be written as inline style attributes on each element.

Images: dual width specification

Set image width as both an HTML attribute (width="80") and inline CSS (style="width:80px;max-width:80px;") to prevent DPI scaling bugs.

Web-safe fonts only

Google Fonts and Adobe Fonts cannot load in email. Use: Arial, Helvetica, sans-serif or Georgia, Times New Roman, serif.

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