How to make TextField constraints in Swift 3?

Question

iOS

Hello, friends!
I ran into a small problem, and before writing here, I dug around the Internet quite well, but I didn’t find anything worthwhile.
The problem is that some TextField fields need to be limited: somewhere there is a character limit, somewhere there are restrictions on entering certain letters. I found one screen, but, having tried, alas, nothing happened. Maybe someone has already encountered a similar problem and found a solution? I will be glad for any help. Thank you.

Answer 1

They dug badly. Second link: tyk