Clean iPhone/iPad: Power off the device, remove from case then wipe clean (replace case if needed)

Clear unwanted clutter (need at least 6GB of free space to update iOS/iPadOS): Go to Settings ❯ General ❯ iPhone/iPad Storage ❯ see which apps are using the most. Make sure Photos is set to ‘Optimise iCloud Storage’ in Settings ❯ Apple ID ❯ iCloud ❯ Photos

Remove unwanted apps: From Home Screen, touch and hold on app and tap on ‘Uninstall’

Search Google for solutions to iPhone/iPad issues: type most important word first. Consider replacing device if over 3 years old. For security reasons replace if the operating system is no longer supported – typically when over 4 years old.