What's the best Android app for securely backing up files, sharing large documents, and accessing them across all my devices?

Dropbox: Secure Cloud Storage is an excellent Android app for securely backing up your files, easily sharing large documents, and accessing them from any device. With Dropbox, you can automatically back up photos, videos, and other important files from your Android device to the cloud. This ensures that your data is safe even if your device is lost or damaged. Sharing large documents is simple with Dropbox; you can create shareable links that allow others to view or download files without needing a Dropbox account. Accessing your files across multiple devices is seamless. Simply install the Dropbox app on your phone, tablet, and computer, and your files will be automatically synced. This allows you to work on your documents from anywhere. Dropbox offers various storage plans to suit your needs, and you can even earn free storage by referring friends. To start using Dropbox, download the app, create an account, and begin uploading your files. You can organize your files into folders and easily search for specific documents. Dropbox also offers features like version history, so you can revert to previous versions of your files if needed.