Google Drive
If you only use Apple devices, then iCloud will be the best cloud service you can use. If you like using other platforms, though, or you’re looking to have some extra cloud space for free, you should check out Google Drive.
Like any other Google app, Google Drive can be accessed on just about any device you may be using. You can also quickly share your files with anyone no matter which platform they’re on, since it’s highly likely that they’ll have a Gmail account — and even if they don’t, you can easily share a file or folder using a secret link.
On top of that, Google Drive is really good at protecting all your files. You can lock the app with Face ID so only you can open it, and add highly secure two-factor authentication to your Google account, so no one can try to snoop through your private files in the cloud.