Filtering documents in the mobile app work like a combination of the deal board and documents tab that's in the web app. You get a helicopter view of all your documents and can easily take action on the deals that's about to expire.
How to filter documents in the Mobile App
Click on the Folder icon second from the left at the bottom of the app.
Then click the funnel on the up right-hand side and choose how you would like to filter your documents.
Click on the option you would like to see.