How do you close a function?

I have a few things to say, firstly, as @slime_bunny_222 said: what level are you on? Secondly: please could you give more information about your problem. What do you mean when you say ‘close’? Do you mean complete the function as it says here?:

Finally, please could you fully format your code, you’ve only formatted one line at the moment. You can look at this topic for a refresher:
How to Post Your Code With Radiant, Harmonious Formatting