The Integration view in Email Delivery has information and fields to set up the following features:

Email API Key Generation The API Key is required for each command to send to the API. Use the Email API Key Generator to create the API Key for your Email Delivery account. See the help topic Generating an Email API Key for more information.
Postback URLs Bounce or spam complaints returned for your outbound messages can be forwarded to your system. Create the URLs to handle these items. List Unsubscribe requests can also be handled in this way. See the help topic Email Postback URLs for more information.
Custom X-Headers There are four custom field values you can use to label your outbound emails. See the help topic Email Custom X-Headers for more information.