Outlook 2013 allows you to create one default signature and multiple alternative signatures, while the Outlook Web App only provides the option to create and use one signature. Note that the Outlook Web App does not provide you the option to include an image file with your signature. In the Edit signature field, create your signature.In the Mail section, click the Signatures… button.To create an email signature in Outlook 2013: How To Create Office 365 Email Signatures However, if you copy an image file from another source and paste it into your signature, it will appear. Using the drop-down menus, select the signature you want to appear appended to new messages and/or replies and forwards.In the Choose default signature section, select the email account to associate with the signature, if applicable.The first signature you create will be called “default.” To rename, click the Rename button and type a new name for the signature.You can modify the formatting and click the icons to add images and links.

You can also leave this option as (none).

To create a signature in the Outlook Web App: If you’ve chosen not to automatically add signatures to your Outlook 2013 emails, you can insert a signature manually by selecting the Insert tab in an email window, selecting Signature, and choosing the signature you’d like to insert.

How to add logo to email signature in outlook