Some apps are built into iOS and won’t let you delete them—like Photos or Safari. That’s okay! You can just tuck them into a folder called “Junk Drawer” so they’re out of sight.
If you want to truly delete a built-in app on iPhone 7, you can hide it from your home screen. Go to Settings > Screen Time > Content & Privacy Restrictions, and toggle off the apps you never use.
But for most third-party apps—like that budgeting tool you abandoned or the second photo editor—hold and tap X. You’ve got this.