Hello, looking for a few apps and wondering which are the best in these categoriesaid or free, doesn't matter: -PDF Reader. Whichever will handle large files -Voice Changer. something i can use to change my voice when i call someone. -Number changer. something i can use to change my number in appearance to the number i call. -Folder locker. a password protected folder for vids, pics, and files. Any suggestions would be great! Thanks!