Is there any difference between writing in a ubuntu@ubuntu and root@ubuntu

Yes, ubuntu@ubuntu is a default standard user while root@ubuntu is an administrator user, certain commands can only be executed by administrators unless explicit permission is provided to the user

so we can go with ubuntu@ubuntu?

yes you can go with ubuntu@ubuntu, and if you get permission issues, you can add ‘sudo’ in front of the command and enter the password of the root user to execute the command as root user
or change your user with ‘sudo su’