Note: The Files app is only available on devices running on iOS 11 or later.
Add and access all your files from your iOS device's Files app. Third-party apps like OneDrive, Dropbox, Box, Google Drive, or Adobe Creative Cloud. The files you save to the Files app on your iOS device show up automatically, but you’ll need to set up other third-party cloud storage services to get access to them in Files.
Here's how to add third-party apps on iOS:
Download the app from the iOS App Store and log in to it.
Open the Files app.
Tap Browse (in the bottom right corner).
In the top right corner, tap More > Edit.
Turn on the third-party app by swiping right on the toggle.
Note: These are directions for iOS 13 and later. For devices running on iOS 12 or earlier, open the Files app then tap Locations > Edit to add third-party apps.
Now, when you go to upload a file to Teams from your iOS device, you'll be able to access them from any of your third-party apps.
Looking to add cloud storage to Teams for desktop or web? Check out Add a cloud storage service to Teams.