Hi Farah,
Unfortunately, there is not a native option available to Account Admins to hide an application from being viewed on the My Apps page of users who have accessed the application. The My Apps page serves as a hub for application access in an Account and recently accessed applications display there. If you feel that having an option to restrict which apps can show up on the My Apps pages for users I would suggest adding that feedback on our User Voice page. The Quick Base User Voice can most easily be accessed from the My Apps page in Quick Base by clicking on the orange Feedback tab in the left of the page or at
http://quickbase.uservoice.com. This forum is used by our development team to explore customer suggestions for enhancements / changes to the platform. I'm sorry there isn't a fix I can point you to at this time. I would suggest if you put the user voice request in that you also add it here to this Community post as that will help other users who share your need find the request and add their votes.
