Office 365 (Outlook 2013) - 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.
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.