The iOS Mobile SDK allows you to capture in-app referrals, and easily record any sales that occur on the back of these referrals within your iOS application. It supports both Swift and Objective-C.
The SDK provides two model classes; Conversion and ConversionItem. The Partnerize class is also used to provide functionality for dealing with inbound clicks, the combination of these classes enables the following features within your iOS app.
Click reference retrieval from inbound requests. Conversion creation with a range of attributes including custom metadata. Conversion item support for accurate shopping basket representation. Deep linking support for Web to App and App to App.
Partnerize App Tracking iOS framework supports iOS 9 and later.
https://performancehorizongroup.github.io/partnerize-mobile-sdk-ios/
There is an example app provided here for Swift.