This confusion is so similar to practice and practise that once you've learned the difference for one, you instantly know it for the other!
When you install a TV in your home, you must have a TV licence. The TVLA (0800 0324690) license you to watch TV.
In the USA they use "license" as a noun. Since computer software comes with a licence for you to use it, this is commonly misspelled as license.
A software licence is often printed on paper - like a certificate. So the critical last two letters remind you of this fact - a licence is a thing (noun).
"Ed didn't have a fishing licence - the council had decided not to license anyone new this year to conserve stocks."