Navigate to Email Review Signature
Follow the instructions for your email client. Generally, you will copy the code displayed at the top of the screen (this code is unique to your account) and paste it into your email client. You can find full instructions for the following email clients on the Email Review Signature page:
Outlook for Windows
Outlook for Mac
Inbox by Gmail
For any client not listed here, the process is similar. Consult the documentation for your email client and copy the code into the appropriate place.