MESA (Member Enrollment Self-Service Access) is a web portal that allows users to view claim details and status, search for claims, and access resources like claim forms. To create a login, users enter their email and select member, then enter their certificate ID with two zeroes. They create a password with a symbol and capital letter that is at least 7 characters. The portal then allows viewing claims, coverage history, and resources. If an error occurs, users can select that they don't know their client ID or code and enter contact details to be assisted.