title: Typing always (force) lowercase or uppercase - iOS swift
body: <p>How to force to type always lowercase or uppercase for some textfields in <strong>swift</strong> language?</p>
  <p><a href="https://i.stack.imgur.com/Cn4nd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Cn4nd.png" alt="mixed lower and upper" /></a></p>