MYSQL Database Password Set

How can I set the database password for my sql database?

I am using ubuntu with apache, php, and my sql installed.

I followed this to create the database and import the sql file.

https://www.digitalocean.com/community/tutorials/how-to-import-and-export-databases-in-mysql-or-mariadb

Now I need to get my code to connect to the database.

How do I set the database password? Or is that just the mysql root password?