Hello, I have a question, will the eye tracking feature also be available on the iPhone 11?

From announcements so far, it seems that this upcoming iOS 18 feature would be supported on all iPhones and iPads that can run iOS 18, so including iPhone 11.

Apple announces new accessibility features, including Eye Tracking - Apple Newsroom

Possibly.

Eye tracking is mentioned in the iOS 18 preview: iOS 18 Preview - Apple

The iPhone 11 is on the device compatibility list for iOS 18.

With that said, nobody here knows if all features will be available to every device on that list.