As this is a cPanel web hosting platform, databases can only be created through the cPanel interface - they cannot be created through command line nor phpMyAdmin. The easiest way to create a new MySQL database and user is via the MySQL Database Wizard. Note: if you are using Installatron/Softaculous to create a CMS, these app installers will create a database and user on your behalf.
Creating a database from the MySQL Databases section of cPanel
Using the MySQL Databases section is a little less straightforward, but it provides more freedom by allowing you to link additional users to a database (allowing multiple).