root user account in Ubuntu Linux

After installing Ubuntu Linux, I tried to install some softwares, but i don't have "Super user" or Administrator privileges. I know in some Linux "root" user like administrator account in Windows. I tried but i don't have have any user with name "root".

Then i found, the user I created when installing Linux itself a super user account.
Whenever I need Administrator privileges I need to use "su" command in Terminal to become super user.