my phone has apps I no longer use that are taking up much space causing my phone to not work properly. How do I delete this apps

Unless you have restrictions (in the Screen Time settings I believe) on deleting apps, you can hold down until an X shows up and tap on the X. It will ask if if you wish to remove the app or just put it away. If you can't find an app icon you can just swipe left for the App Library to show up and look there where you can remove an app.