During the preview phase of the Mail Singuate, you will need to obtain the Mail Signature manifest file from officeatwork and uploading to your Microsoft 365 tenant during the process of deploying the Mail Signature App via Microsoft centralized deployment.Once the Add-in is deployed it will generate a default signature with your name, e-mail, and phone number sourced from Azure AD.To configure your own signature you would need to launch the officeatwork Admin center. This feature should be coming soon.Delay: please note that it can take up to 24 hours for the Add-in to appear in Outlook.Check: the easiest way to check your deployment is to launch Outlook Online with a user you have assigned the Add-in to.