AccuZIP (https://accuzip.com) is a company specializing in mailings and managing the requirements of the USPS. In order to use the EDDM functions of wp2print, you will need to create an account with AccuZIP. Once you have created your account with AccuZIP, they will provide you with an API key.
Here is the items that can be configured for the functioning of the EDDM system: