First of all you should know how you can add users in mysql databases:-

• Using CREATE USER and/or GRANT commands
• Inserting a new record into the mysql.user table

First let’s see how to use the CREATE USER command:-

     CREATE USER user [IDENTIFIED BY [PASSWORD] 'password']

e.g

mysql>CREATE USER 'myuser'@'localhost' IDENTIFIED BY 'mypassword';

Once user added in databases you need to provide privileges to that user.You can use like:-

mysql>GRANT SELECT,INSERT,UPDATE,DELETE ON *.* TO 'myuser'@'localhost';
or mysql>GRANT ALL ON *.* TO 'myuser'@'localhost';

Another way for creating users in mysql is just enter directoly in user table of mysql and make few entries:-

mysql> INSERT INTO user VALUES('localhost','monty',PASSWORD('some_pass'),
     'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y');
or
mysql> INSERT INTO user (Host,User,Password) VALUES('localhost','usename','pass');
mysql> FLUSH PRIVILEGES;