My FaceTime app has disappeared

Whether or not you'll be able to get FaceTime depends on where it came from and where you are:

1. iPhones which have AB or AE just before the slash in their model numbers will only have FaceTime in Egypt, Qatar, Oman, Jordan, Lebanon, Bahrain, Kuwait, or Saudi Arabia; for the last country, it'll need to be running at least iOS 11.3 and the current carrier settings.

2. iPhones which have UR just before the slash in their model numbers will only have FaceTime in Pakistan, and need to be running at least iOS 12.4.

3. iPhones which have different letters just before the slash in their model numbers will have FaceTime worldwide. If it's missing on these, check the Screen Time restrictions, search for it, or redownload it from the iTunes App Store.

You could search it up on the app store and it should show up. Should you have any further questions, contact apple support.