When you store data on your phone, it is stored in a file system. This is a system that organizes all of the files on your phone and makes them accessible to you. Each time you add or remove a file, the file system updates itself so that it can keep track of all of the files on your phone.
The file system on your phone is important because it helps to keep your data organized and accessible. Without it, you would not be able to find the files you are looking for or use them in the way that you want to. If you are having trouble accessing a file on your phone, it may be due to an issue with the file system.