A licence is a permit to do something. You need a licence to drive a car. If you spell it licence instead of license, then you’ll be driving on the left side of the road because the “c” ending is British.
A licence, spelled with the “c,” is a noun — like that driver’s licence in your wallet that allows you to drive all over England. In British style, the word license (with an “s”) is only a verb and licence is a noun. So if you can put a/an/or the in front of it, it’s a licence. James Bond had a Licence to Kill in the movie of the same name. Don’t ask to see it!