Permit or permission?

The countable noun permit (pronounced /ˈpɜ:mɪt/) refers to an official document that allows you to do something or go somewhere. The uncountable noun permission refers to when someone is allowed to do something. It does not refer to a document:

• You need to have a work permit before you can work.
• Not: You need to have a work permission ...
• I have a parking permit which allows me to park on the street outside my house.
• Not: I have a parking permission ...

We use the word permission with an infinitive with to:

• Could I have your permission to leave work early on Friday?
• We applied for permission to build a house here but our application was refused.