I don’t have a computer

You do not require Mac/PC for updating iOS or Carrier updates

1. Update your iPhone, iPad, or iPod touch
   1. Plug your device into power and connect to the Internet with Wi-Fi.
   2. Tap Settings > General > Software Update.
   3. Tap Download and Install. If a message asks to temporarily remove apps because iOS needs more space for the update, tap Continue or Cancel. ...
   4. To update now, tap Install. ...
   5. If asked, enter your passcode.
   6. Update your iPhone, iPad, or iPod touch - Apple Support
2. Carrier Settings Update
   1. You can manually check for and install a carrier settings update with these steps: Make sure your device is connected to a Wi-Fi or cellular network.
   2. Tap Settings > General > About. If an update is available, you'll see an option to update your carrier settings.
   3. Update your carrier settings on your iPhone or iPad - Apple Support