While using the command "sudo" can perform all administrative actions of our system it is possible that we occasionally see the need to activate the superuser root of our Ubuntu installation. In any case have disabled root is a good security policy.

To enable root we use the following command that will assign a password:

sudo passwd root

Then we open session with him or be able to use the command su

By the time we decide to disable root use the command:

sudo passwd -l root

It should work with all editions of Ubuntu.