// Private app data — persistent, backed up by Android
var dataPath  = FileSystem.AppDataDirectory;

// Cache — may be cleared by the system to reclaim space
var cachePath = FileSystem.CacheDirectory;

// Write a text file
var filePath = Path.Combine(dataPath, "notes.txt");
await File.WriteAllTextAsync(filePath, "Hello from MAUI!");

// Read it back
var content = await File.ReadAllTextAsync(filePath);

var result = await FilePicker.PickAsync(new PickOptions
{
    PickerTitle = "Select a document",
    FileTypes   = FilePickerFileType.Pdf
});

if (result is not null)
{
    using var stream = await result.OpenReadAsync();
    // process stream...
}

var photo = await MediaPicker.Default.PickPhotoAsync();
if (photo is not null)
{
    var stream = await photo.OpenReadAsync();
    ImageView.Source = ImageSource.FromStream(() => stream);
}