This is how to locate what users you have created on the mySQL server.
First log into your server
mysql -uroot -p
To list your users do the following:
mysql> SELECT user,host FROM mysql.user;
This will the print out all the users and their host for example:
+------------------+-----------+
| user | host |
+------------------+-----------+
| paul | localhost |
| mysql.infoschema | localhost |
| mysql.session | localhost |
| mysql.sys | localhost |
| root | localhost |
+------------------+-----------+
If you wish to delete a user for what ever reason. You will need to run the following, for example lets delete user paul
mysql> DROP USER paul@localhost;
You can also delete multiple users buy just adding commas such as:
mysql> DROP USER paul@localhost, root@localhost;
But I wouldnt suggest deleting your root
user.