App extensions Extend your app’s basic functionality to other parts of the system. TopicsExtension supportNSExtensionRequestHandlingNSExtensionContextDocument providerNSFileProviderExtensionUIDocumentPickerExtensionViewControllerCustom keyboardUITextDocumentProxyUIInputViewAudioFeedbackUIInputViewControllerUILexiconUILexiconEntry See AlsoApp structureApp and environmentDocuments, data, and pasteboardResource managementInterprocess communicationMac Catalyst