Admin needs root password

I recently installed it and since I am the only user the system asks me for root password if I want to install something or read any files. Always saying that I don't have permission to access.

Before the installation I had Kali Linux on a boot stick with persistence, actually just for school. So I'm coming to the point: Why didn't the system asked me for a root password when I had the boot stick? Now I always have to type sudo for everything and that's aoying.