Tier 1 (AGK Basic)?
If so, you just copy over the project from the PC to the Mac, and open the project in the Mac AppGameKit IDE. It should run just fine. However, there are some gotcha's with video-playback on Mac/iOS. Apart from that, you'll need a dev account with Apple to be able to generate a certificate that you need on the Mac key-chain - and download latest XCode which you'll need installed, and you need a provisioning profile to sign the app with. Once both those are downloaded, just export an IPA for iOS the same way you export an APK in the AppGameKit IDE and supply the different files and media (icons) it needs.
For upload to App-Store, you need the App-Uploader app on Mac (which I can't quite remember what is called), and when the IPA goes through, fill out details at the AppstoreConnect website. Once all is good to go, click 'Submit for Review' and await the inevitable rejection from Apple, and them asking you to change this, that and the other thing before resubmitting.