Look in Settings
Go to Settings > General > About. To the right of Model, you'll find the part number. To find the model number, tap the part number.
Look on your device
On an iPhone 8 or later, to find the model number, remove the SIM tray and look in the SIM tray slot. Make sure that you're in a place with bright light overhead. The model number is on the upper side—the side with the display. On iPhone models that support eSIM only, you can find the model number in Settings > General > About. If you can't turn on your device to find the model number, contact Apple Support.
On an iPhone 7 or earlier, an iPad, or an iPod touch, find the model number on the back of your device.