Should I use licence or license?
These tend to be used interchangeably now but, strictly speaking (unless you are in the USA):
Licence is the noun - therefore it is the thing such as a driving licence - a certificate, or document giving permission to do something.
License is the verb - it is the act of granting a licence or giving permission to someone.
"I license you to use this licence."
The DVLA will license you - you will then carry a driving licence.
The easiest way to remember this is to think of a certificate - this is a noun and so is a licence.
If that's not enough, think about sending something in the post. Sending is a verb and so is license.