Let's briefly touch the topic of a document provider. A document provider extension lets you play with other apps. These extension allows other apps to access the documents managed by your app. Documents managed by your document provider extension can be accessed by any app using a document picker view controller, which we see in the example here. When users open or import files, show only context specific documents and information when someone uses your extension to open or import documents, only display documents that are appropriate for the current context. For example, if a PDF editing app loads your extension, only these PDF files as possible documents that can be opened or invalid.

Be sure to leave other information that may be helpful to such as modifications dates, sizes and whether documents are local or remote. Let people select the destination when exporting and moving documents. Unless your app stores documents in a single directory, let users navigate to a specific destination in your directory hierarchy. Consider providing a way to add new sub directories don't provide a custom navigation bar, your extension loads within the modal view that already includes the navigation bar. Providing the second condition bar is confusing and take space away from your content of course.