How to remove an app from my iPhone?

Various ways depending upon the iOS version on the device and type of app:

How to delete [third party] apps on your iPhone, iPad, and iPod touch - https://support.apple.com/HT207618

Delete [and restore] built-in Apple apps on your iOS 12, iOS 13, or iPadOS device or Apple Watch - https://support.apple.com/HT208094 - "When you delete a built-in app from your device, you also delete any related user data and configuration files."

Delete built-in Apple apps from the Home screen on your iOS 14 or iPadOS device or Apple Watch - https://support.apple.com/HT211833