How to update it without computer

IOS Update or some other update?

IOS

Is your device compatible to update to the new version? See the Apple Support article(s) below. 

iOS 14 and iPadOS 14 Compatible Devices

iOS 13 and iPadOS are compatible with these devices - Apple Support.    

iOS 12 is compatible with these devices.    

IOS 11 is compatible with these devices    If you can upgrade to IOS 11, you can upgrade to IOS 12

IOS 10 is compatible with these devices    

Update your iOS device.        

Get help with over-the-air iOS updates          

Update – Can’t or can’t restore 

If you see an error when you update or restore your iPhone, iPad, or iPod