Office 365 (Outlook 2013 / 2016 for Win) - Add a Signature to Messages
You can create personalized signatures for your email messages that include text, images, your electronic business card, a logo, or even an image of your handwritten signature. You can set it up so that signatures can be added automatically to all outgoing messages, or you can choose which messages include a signature.
NOTE: If you are using both the Outlook Client and the Outlook Online, you need to create a signature in each platform.
Set up a signature to appear automatically in every email you send:
1. On the Home tab, click New Email.
2. Click the Message tab.
3. In the Include group, click Signature, and then click Signatures.
4. Under Choose default signature, in the E-mail account list, click an email account to associate with the signature.
5. In the New messages list, select the signature that you want to include.
6. If you want a signature to be included when you reply to or forward messages, in the Replies/forwards list, select the signature. Otherwise, click (none).
Insert a signature manually:
1. In a new email message, click the Message tab.
2. In the Include group, click Signature, and then click the signature that you want.
TIP: To remove a signature from an open message, select the signature in the message body, and then press Delete.