Here are the steps to enable mobile only products -
Go to Shopify store.
Go to products & select products you want to show only on Mobile App.
3. Go to Actions > Make Products Available, select Mobile App Creator. Save.
4. Go to Actions & Make Products Make Products Unavailable, deselect Mobile App Creator. (Deselect only Mobile App Creator)
These changes are real-time, you can check the app right away.
Hope this article was helpful :)