Assuming you would like a step-by-step guide on how to block an app on your iPhone:
1. Open Settings and tap Screen Time.
2. Tap Content & Privacy Restrictions. If asked, enter your passcode.
3. Tap Allowed Apps.4. Select the apps that you want to allow and tap Add.5. To block an app, don't select it under Allow Apps.*
6. Under Always Allowed, select the apps that you want to allow, even during Screen Time limits. Or turn off Always Allowed altogether to limit access to all apps at all times.*
7..Tap Back, then tap Continue.* And that's it! The app is now blocked from being used on your device (unless you've selected it as an Always Allowed app).