How to create a Postgre user?
In order to create a PostgreSQL user you should go to your cPanel -> PostgreSQL Databases interface.
In the Add New User form enter the username and password. Note that the username will always include your cPanel username as a prefix.
Then you can add the newly-created username to an existing database. For this purpose use the Add User to DB form. All you need to do is select the corresponding database and user and then click the Submit button.