Some app can accept multiple files (such as Shu from PixelCyber). According to the file path after importing, I think they do this by using AppGroup. I guess after user selected multiple files and tapped the app icon in the share sheet, a ShareExtension with no UI was opened to copy files to AppGroup storage. After copy is done, ShareExtension just open the main app with extra information to notify main app about the imported files in the AppGroup storage.

Thank you for your reply. Multiple files are imported by selecting and sharing files in Files app and choosing my app in the share sheet. The corresponding file types have been declared in the "Document types" section of Info.plist, therefore my app's icon will appear in the share sheet. It will be convenient if I can import multiple files with one open, instead of opening my app multiple times or creating a zip or folder.

Thank you for your reply. Multiple files are imported by selecting files in Files app and choosing my app in the share sheet. The corresponding file types have been declared in the "Document types" section in the Info.plist. Therefore my app's icon will appear in the share sheet to allow user to select my app. These files are of custom file types to share individual data of my app. It will be convenient if I can import multiple of those files, instead of importing one by one or creating a zip.