How to Add a Signature to Yahoo Mail

On Desktop

Open Yahoo! Mail. Go to https://www.yahoo.com/mail in your preferred browser. This will open your Yahoo! Mail inbox if you're logged into your account. If you aren't logged into your Yahoo! account, enter your email address and password when prompted.

Click Settings. It's in the upper-right side of the Inbox page. A drop-down menu will appear. If you're using the old version of Yahoo! Mail, first click the blue One click away from your upgraded Inbox tab in the lower-left side of the inbox. This will update your inbox to the newest version of Yahoo! Mail, which is the version covered by this article.

Click More Settings. This option is near the bottom of the drop-down menu. Doing so prompts the Settings page to open.

Click the Writing email tab. It's on the left side of the page. You should see the "Writing emails" column of options appear in the middle of the page.

Enable your signature. Below the "Signature" heading, click the white switch to the right of the Yahoo! email address for which you want to enable a signature. The switch will turn blue, and a text box will appear below the account address. If the switch is blue, the signature is already enabled for this account.

Create a signature. Click the text box below the account address, delete any text in it, and type in the signature that you want to use. This signature will appear at the bottom of every email that you send. You can format your signature's text by selecting it and then clicking one of the options at the bottom of the signature text box.

Click Back to Inbox. This link is in the upper-left side of the page. Doing so will save your changes and return you to the inbox; all future sent emails will display your chosen signature at the bottom.

On Mobile

Open Yahoo! Mail. Tap the Yahoo! Mail app icon, which resembles a purple box with a white envelope icon on it. Doing so opens your inbox if you're logged into your Yahoo! account. If you aren't logged into Yahoo! Mail, select an account (or enter an email address) and then enter your password before proceeding. Changing your signature in the Yahoo! Mail app won't affect the signature that you use when sending emails from the desktop site.

Tap ☰. It’s in the top-left corner of the screen. A menu will open.

Tap Settings. You'll find this near the middle of the menu.

Scroll down and tap Signature. It’s in the "GENERAL" section. Doing so opens the Signature menu.

Tap the white "Signature" switch iPhone Switch Off Icon. This is in the upper-right corner of the screen. It will turn blue, signifying that the signature feature is now enabled for this email account. On Android, this is the "Customize for each account" switch. If the switch is already blue, the signature feature is enabled.

Tap the text box to edit your signature. The default signature says "Sent from Yahoo Mail for iPhone/Android", but you can delete what’s there and add your own text. Otherwise, skip to the next step.

Tap Done. It’s in the bottom-right corner of signature box. Your new signature will be applied to all future emails sent from your iPhone or Android. On Android, you can just tap the "Back" button to save your signature.