Linux has one special user called root (this is the user name). Root is the "system administrator" and has access to all files and folders. This special user has the right to do anything.

You should never log on as this user unless you actually need to do something that requires it!

Use sudo - to temporary become root and do the things you need, again: never log into your system as root!

Root is only for system maintenance, this is not a regular user (LindowsOS don't have any user management at all and uses root for everything, this is a very bad idea!).

You can execute a command as root with:

sudo -c 'command done as root'

Gentoo Linux: Note that on Gentoo Linux only users that are member of the wheel group are allowed to su to root.