The Document Browser
The first screen you'll see when you open 3D Scratchpad, common to many iOS apps, is called the Document Browser. Use the Document Browser to navigate to files and folders on your device and iCloud Drive, and to create and open documents.
Tap on Create Document to create a new 3D model and begin editing.
Tap on an existing .usdz file to open it in 3D Scratchpad.
USDZ files not created with 3D Scratchpad will open for viewing in Object Mode and in AR Mode, however 3D Scratchpad is only able to edit files originally created by 3D Scratchpad.
The Document Browser may also be used to share, rename, copy, and paste documents, as well as many other useful functions.