There is a project for Android on Github:
According to the readme:
The ShowcaseView library is designed to highlight and showcase specific parts of apps to the user with a distinctive and attractive overlay. This library is great for pointing out points of interest for users, gestures, or obscure but useful items.
I would like to know if a functionally equivalent one exists for iOS. It would be useful to give users a quick tour of an app. Typically app intros are handled with a few swipe screens. Think Uber and Duolingo.
Google and Stackoverflow searching returns nothing meaningful. If I had time I'd work on this as a side project.
Edit: I've ended up using github.com/IFTTT/RazzleDazzle which works for both Swift and Objective-C.
You can also try https://github.com/rahuliyer95/iShowcase this is a similar implementation of ShowcaseView for Android on iOS.