If you are getting a message that states an update is available, tap Install Now on your device.

You can also follow these steps: 

  1. Plug your device into power (if your device is under 50%) and connect to the Internet with Wi-Fi.
  2. Go to Settings > General, then tap Software Update.
  3. Tap Download and Install.
  4. Input your password (if any) and await installation to complete

Update your device using your computer

If you can’t update wirelessly on your device, you can update manually using a computer that you trust. If your computer is using Personal Hotspot on the device that you’re updating, connect your computer to a different Wi-Fi or Ethernet network before you update.

  1. On a Mac with macOS Catalina 10.15, open Finder. On a mac with macOS Mojave 10.14 or earlier, or on a PC, open iTunes.
  2. Connect your device to your computer.
  3. Locate your device on your computer or in iTunes.
  4. Click General or Settings, then click Check for Update. 
  5. Click Download and Update.
  6. If asked, enter your passcode and await update completion.