The database user is an access created specifically only for the database.
Just like how our cPanel had an account login and password, so does our database. The level of access is as follows: WHM > cPanel > Database User > Website User
(An FTP User can access the files on the server but not necessarily the database)
Anyone on the upper level has access to the users and accounts in the lower levels, but the lower levels cannot access what is above. This means a cPanel account can modify the database user but a database user cannot access the cPanel.
Scroll down to the section labelled: Add New User
Give your database a username and press Create User. Make sure it isn’t something too easy that your site database will be easily compromised!
Your database user is ready to be added to it’s database!