Not App Store
The App Store is not on my phone at all?the App Store was there and then it disappeared
Question marked as
The App Store is not one of the built-in apps that can be deleted. The usual reason for it not being visible is a restriction on purchasing. See: Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support
If that isn't the reason, try using Search to locate it. Use Search on your iPhone, iPad, or iPod touch – Apple Support