Your question is too vague - there are many components that the word intake can apply to. Generally speaking an intake is something that is part of the process of something going into something - a cold air intake in a car is a setup to try to get cool air into the engine for combustion. A ram air intake is similar but is positioned to allow air to get forced in when you are driving.

What is a "sheltee"?

Do you mean an air intake? or water intake? An intake does exactly what the word says. In a naturally aspirated car motor, the air intake sucks in air (in the carburetor), to mix with gasoline for combustion.

I was wondering wat an intake is before i gi o to the sheltee

Your nose lol.