There are a few ways to format your iPhone 11. You can do a full factory reset, which will erase all content and settings from your device. You can also wipe your device clean and start fresh, which will remove all of your personal data but keep your settings and apps intact. You can also reset your device to its factory settings, which will erase all content and settings and return your device to its default state.
To do a full factory reset, go to Settings > General > Reset > Erase All Content and Settings. This will delete everything on your device, including your apps, photos, videos, and personal data.
To wipe your device clean and start fresh, go to Settings > General > Reset > Reset All Settings. This will remove all of your personal data from your device but keep your settings and apps intact.
To reset your device to its factory settings, go to Settings > General > Reset > Reset Factory Settings. This will erase all content and settings from your device and return it to its default state.