How to Add a Signature in Outlook 365

The quickest way to add a signature

Open Outlook 365 and go to File > Options > Mail > Signatures. Click New, give your signature a name, type or paste what you want to appear at the bottom of your emails, then click OK. From that point forward, Outlook will automatically add it to every new message you send.

If you use multiple email accounts in Outlook, you can create different signatures for each one. You can also set a default signature for new messages and a different one for replies and forwards — useful if you want your main signature on new emails but something shorter on threads you're continuing.

Key Takeaways

Signatures are created in File > Options > Mail > Signatures, not in the message itself.
You can create multiple signatures and choose which one Outlook uses for new messages versus replies.
Signatures can include text, your contact details, a job title, or a company logo if you paste an image.
Once you set a default signature, Outlook adds it automatically — you do not have to copy and paste it into each email.

Creating your first signature step by step

In Outlook 365 on your computer, select File in the top left corner. Then click Options at the bottom of the menu that appears. A window opens; on the left side, click Mail. In the middle column, scroll down until you see Signatures and click it.

You will see a section labeled E-mail Signature. Click the New button. A small box appears asking you to name your signature — you might call it "Work" or "Professional" or just "Default". Type a name and click OK. Now you are in the editing area where you type or paste the text you want to appear at the bottom of your emails.

Type your name, phone number, job title, company name, or any other information you want included. You can press Enter to move text to a new line. When you are done, click OK at the bottom of the window. Your signature is now saved.

Setting which signature appears in new emails

After you create a signature, you need to tell Outlook when to use it. In the same Signatures window, look for the section labeled Choose default signature. There are two dropdown menus: one for New messages and one for Replies and forwards.

Click the dropdown under New messages and select the signature you just created. If you want a different signature (or no signature) on emails you are replying to, change the Replies and forwards dropdown separately. Most people use the same signature for both, so you can set them both to the same one. Click OK when you are finished.

Using different signatures for different email accounts

If you have more than one email account set up in Outlook 365, you can create a separate signature for each. In the Signatures window, the dropdown at the very top says E-mail account. Click it and select the first account you want a signature for. Create and name a signature for that account, then click OK.

Go back to File > Options > Mail > Signatures, click the E-mail account dropdown again, and select your second account. Create a different signature for that account if you want. Set the defaults for each account separately. Now when you compose a new email, Outlook will automatically use the signature that matches whichever account you are sending from.

Adding images or formatting to your signature

The signature editor in Outlook 365 lets you do more than plain text. You can make text bold or italic, change the font, or add a company logo. Highlight the text you want to format and use the buttons in the toolbar above the editing area — they work the same way as formatting in a Word document.

To add an image like a logo, click in the signature box where you want the image to go, then click the Insert tab at the top of the window (this appears when you are editing a signature). Click Pictures and choose the image file from your computer. The image will be embedded in your signature. Keep images small — a logo should be no more than 100 pixels wide so it does not make your emails look cluttered.

Troubleshooting signatures that do not appear

If you created a signature but it is not showing up in your emails, check that you set it as the default. Go back to File > Options > Mail > Signatures and make sure the New messages dropdown is set to your signature name, not blank. If it says None, click the dropdown and select your signature.

If you are composing an email and the signature still does not appear, check whether you are replying to an existing email or starting a new one. Replies use the Replies and forwards setting, which might be set to None. Also check that you are using the correct email account — if you have multiple accounts and the signature is only set for one of them, it will not appear when you send from a different account.

On the web version of Outlook (outlook.office.com), signatures work differently and are created in Settings > Mail > Compose and reply. If you are using Outlook on the web instead of the desktop app, look for that menu instead.

When you might want multiple signatures

Creating more than one signature is useful if you wear different hats in your work. You might have a formal signature with your full title and company information for client emails, and a shorter casual one for internal team messages. You can switch between them manually when composing an email by clicking the signature dropdown in the message itself.

Some people also create a signature for personal emails separate from work emails. If you have a Gmail account and a work account both open in Outlook, you can set a professional signature for work and a straightforward one with just your name for personal messages. The signature automatically matches the account you are sending from, so you do not have to think about it.

Frequently Asked Questions

Can I change my signature after I have already sent an email?

No — once an email is sent, you cannot change the signature that is already in it. You can only change the signature for future emails. If you need to update your signature, go back to File > Options > Mail > Signatures, click the signature you want to edit, make your changes, and click OK. All new emails from that point on will use the updated version.

What if I do not want a signature on one specific email?

When you are composing an email, look for the signature dropdown in the message itself (usually near the bottom). Click it and select None. That email will send without a signature, but your default signature will come back on the next email you write. You do not have to change your settings permanently.

Can I use the same signature in Outlook on my phone?

Outlook on mobile devices (iPhone, Android) does not let you create custom signatures the same way the desktop app does. However, signatures you create in the desktop version of Outlook 365 will automatically appear on emails you send from the mobile app, as long as you are signed into the same account.

Is there a limit to how long a signature can be?

Technically no, but very long signatures can look unprofessional and make emails harder to read. Most people keep signatures to five lines or fewer — typically name, title, company, phone, and email address. If you add an image, keep it small so it does not dominate the message.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.