Right click on any song in your iTunes library and select Get Info from the pop-up menu and than click on the Info tab.
You can also select a set of songs, typically all the tracks from a particular album, and right click > Get Info to see/change the metadata that is common to those tracks.
This is also where you can add album art - under the Artwork tab for a single song - or on the Info tab for a whole album.
If you have a “recognized” Cd than you should be able to as iTunes to get the artwork for you - select all the tracks of the album and from the Advanced drop down menu select Get Album Artwork.
WC