The iPhone 11 has a 6.1-inch screen. As a result, cases that fit the iPhone 11 typically have the same size and can cover the entire phone. If you want to buy a case that fits the iPhone 11, choose one with a 6.1-inch screen.
Apple 11 rear cover dimensions: Height :150.9 mm (5.94 in), width :75.7 mm (2.98 in). The case size of the Apple 13 is 6.5 inches, they are not universal, and the rear camera shape is not the same.