Open a new email message. On the Message tab, click Signature, and then click Signatures. In the E-mail account list, pick the email you want. Under Select signature to edit, select New, and type a name for the signature. Type the signature you want in the Edit Signature box. Create an email signature in Outlook for Mac Select New Email. Select Signature > Signatures. Select + and type a name for the signature. Under Signature, type your signature and format it the way you like. Under New messages, select your signature. Select the red circle in the upper left to close. Select New Email to see the signature you created.