Update?
what is a firmware update and how do i install it
iPhone 11
The latest iOS for your iPhone 11 is iOS 16.0.3
To install it, follow the steps mentioned in this article:
Update your iPhone or iPad - Apple Support
If you choose to update wirelessly, make sure to have at least 6 - 10GB free space available on your iPhone.
Updating by using the computer does not require that much free space.