Software updates bring a bunch of new features to the users. They can be handy, crucial, or just fun (think: Memoji Stickers on iOS 13). Anyway, you don't want to miss out on the next cool thing that everyone is likely to talk about.
Before you start: Make sure your data is safely backed up.
Here is how you can update your iPhone, iPad, or iPod touch: 
  1. Plug your device into power.
  2. Connect it to a Wi-Fi network.
  3. Go to Settings -> General -> Software Update.
  4. Tap Download and Install.
  5. For an immediate update, tap Install. 
  6. Enter your passcode, if asked.