As you've learned, positioning can be easily tested on Android with MapCreator's built-in positioning feature.
To test on an iOS device, the simplest way is to use mobile app link that is created from the IndoorAtlas web app.
1. Follow the instructions to create an application and Apikey
2. Click the "Create mobile app link" button
3. Select the Apikey you just created
4. Click the "Copy link" button
5. Send the link to an email account which you can access on the iOS device
6. Click the link on the iOS device. On the first run, it should take you to Apple store to install IndoorAtlas Positioning App. On the following click, the app should open and the apikey gets stored to the application. After this, you can open the app either directly and start position from the app, or open it using the link.