The following use case diagram shows the requirement for Email Formatter:

The actor is the User of the Tweety. It has the following use cases:

• Login: This use case is required to authenticate users so that each user can be uniquely identified to allow only authenticated users to perform actions.
• List Users: This use case is where a user can list all the usernames of available users. It requires the user to be authenticated.
• Reset Password: This use case is where a user can request to reset his/her password.
• Format Email: This use case is where, based on a Reset Password request, an email will be formatted and filled with the relevant user details.
• Send Email: This use case is where an actual Reset Password email is sent to the user's email address.