In your terminal, log into the MySQL as root. You may have created the root password when you had installed MySQL for a first time or a password could be blank, in each case you can simply press ENTER when prompted for your password.
sudo mysql -p -u root
Now add your new MySQL user with a username of your choice. In this example we are reefing it as pmauser (for the phpmyadmin user). Make sure to replace the password_here with your own. You can now generate a password here. A % symbol here tells the MySQL to allow your user to log in from anywhere remotely. If you wanted to heightened security, you could replace it with the IP address.
CREATE USER 'pmauser'@'%' IDENTIFIED BY 'password_here';
Now we will grant the superuser privilege to your new user.
GRANT ALL PRIVILEGES ON *.* TO 'pmauser'@'%' WITH GRANT OPTION;
Then go to the config.inc.php ( in your ubuntu, /etc/phpmyadmin/config.inc.php )
/* User for the advanced features */
$cfg['Servers'][$i]['controluser'] = 'pmauser';
$cfg['Servers'][$i]['controlpass'] = 'password_here';