Uploading Files in iOS

Is there a control or UI where I can choose a specific file to upload to a server? I want it to be able to accept any file types such as .pdf, .doc, etc. The files would be already inside the iOS Device. I know how to transfer the data to a server, but I don’t know how to create the UI where I can choose which file to upload.

Each iOS app runs in its own sandbox. Which means that only files handled by the app can be accessed.
There is no native control to access files, except for pictures with the iOSPicturePicker.

If the file is saved in the App’s xojo.IO.SpecialFolder.Documents, then you could use an iOSTable to show all files.