A cartouche is a name plate. It’s usually oval with your name written in the middle of it. A cartouche is attached to your coffin.
The ancient Egyptians wanted to make sure that their two souls – the Ba and the Ka – could find their way back to their tomb at night, after they died. No one wanted their Ba or Ka to get lost. A cartouche made it very easy for a Ba and Ka to find their way home.
A cartouche was meant to protect against evil spirits both in this life and the afterlife.