So, I heard that it's possible to edit root files on Linux but if I trying to save the file I get this message:
They do not have the necessary authorisations to store the file. Please, check whether you have properly given the place, and try it once more.
So, how can I change root user?
To get root access you can prefix the commands with sudo, for example:
rpi ~$ sudo editor /etc/issue
To get permanent root rights for all following commands you can use:
rpi ~$ sudo -Es
root@rpi ~# editor /etc/issue
root@rpi ~# exit
rpi ~$
You should use this mode with care and leave it as soon as possible with exit. Unix isn't made to work interactive as root.
sudo. – Brick Dec 20 '18 at 17:38