How can I prevent third-party apps from accessing my personal files ?

[EngineerStrange]

How can I prevent third-party apps from accessing my personal files even after allowing the storage permission for them ?

[kc1di]

I think you would get better answers if you give us a little more information on what apps and how they now access those files. You can deny anyone for accessing files of directories by
using the appropriate permissions on that file or directory. See here.

[EngineerStrange]

Actually I'm talking about android apps and my question is on phones not computers.

[coffeecat]

Then please make clear exactly what it is you are asking when starting a thread. The Mobile Technology Discussions sub-forum is a discussion, not technical support sub-forum. Therefore, thread moved to any Other OS.

You would be better asking this question on an Android forum.