Most of the apps don't work on my iPhone

If you have an iPhone 6, as your profile indicates, that is a very old product. The iOS operating system can only be updated as far as iOS 12.5.5 on your phone.......but.......many apps require an iPhone to be running a much higher operating system.

The solution......a new iPhone for you.

You need a new phone. Most apps have been updated to iOS 13 and above.