MySQL Login details

You can find MySQL root password in the file /root/.my.cnf:

Example from the ssh/shell

cat /root/.my.cnf
[client]
password=ydVg5g3Wz2FH
user=root

** MySQL root password in this case would be ydVg5g3Wz2F

Users can log in to MySQL/PhpMyAdmin by using the same login credentials as for the user control panel.
You can also make additional mysql users by using the mysql manager in the admin or user panel.