Shapr3D automatically detects STEP, IGES, SHAPR, image files, and after you tap the file or the Share button in any app the Share window pops up.
Here, you will be able to open these type of files in Shapr3D.
After you have selected Shapr3D, you will be brought there and the following screen will pop up. Decide if you want to import it into your current workspace or you want to create a new one for this file.
Your iPad Pro, since iOS 11, has an app named Files, which allows you to save to/import from your iPad Pro itself, or one of the cloud services (e.g. Dropbox, Drive, iCloud) connected to it.
This flow is typical for all the other apps as well. Tap on the file, and if needed the Share button, then choose Shapr3D from the options.
Here are a couple of other apps that you can import Shapr3D compatible files from:
- and many more