FaceTime is not available in App Store

Hi Sid7379

welcome to the Apple (user-to-user) Community.

Re: "In my iPhone 11 pro max facetime is not available in app store"

You may need to make sure you look for the FaceTime app for iPhone (ie: not iPad, or Mac version):

Eg: https://apps.apple.com/us/app/facetime/id1110145091

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If you haven't deleted the FaceTime app from your iPhone:

The icon for FaceTime may just be missing from the Home screen, while the app is still in the App Library.

You could search for the app in the App Library:

Organize the Home Screen and App Library on your iPhone - Apple Support

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If you have deleted the FaceTime app from your iPhone:

Delete built-in Apple apps from your iPhone, iPad, or Apple Watch - Apple Support

says

"Restore a built-in app that you deleted

1. 1. 1. On your iPhone, iPad, or Apple Watch, go to the App Store.
      2. Search for the app. Make sure that you use the exact name of the app.
      3. Tap the Redownload button .
      4. Wait for the app to restore, then open it from your Home Screen".

More support if needed:

FaceTime support website (info. / support / contact)

FaceTime - Official Apple Support

All the best :-)

What country are you in? In what country did you purchase the phone? Also, go to Settings>General>About>Parts And Service History. Does it say anything about the screen being replaced?