What does the Files app do on my iPad?: Files allows you to easily see, edit and share your files (pdfs, letters, spreadsheets, photos), away from your main computer (Windows or MacOS). Files stored within apps and files stored in iCloud, OneDrive, GoogleDrive or other cloud storage are accessed in Files. If you have a Mac (iMac or MacBook) you should turn on iCloud Drive in iCloud in your Apple ID in System Settings and enable your Desktop and Documents folder. This syncs your files in Finder to iCloud so they are backed up and you can access them on your iPhone or iPad
