Comment by bayindirh

In iOS the same feature appears as "Files integration", which allows you to see an app's files from the "Files" application, and some applications can see all "Files Enabled/Allowed" applications in their file selection window.

Just checked with Dropbox, and yep, that's how it works. Files can access Dropbox transparently, and Dropbox can access any files which can be seen by the Files app.

So an equivalent is present in iOS.