Here's how you can hide specific pages from the mobile app -
Log In to Shopify store
Go to Online Store.
In the online store go to Pages section.
Open the page which you want to hide on app.
In the selected page Go to content section & click on Show HTML(<>) button.
In the show HTML put this code on the header.
<hideonapp> </hideonapp>Save.
Hope this article was helpful :)