I made android unity game, that sometimes working with file system, creating new folder and files, editing those files. When I was testing this on android device, nothing happened with files. I know, the problem is my app does not has android permissions to editing files. Idk how to asking permissions, help me pls

I was trying to ask this permissions by UnityEngine.Android.Permission.RequestUserPermission(UnityEngine.Android.Permission.ExternalStorageRead); but nothing changes.