The Documents app also lets you change the playback speed for. You can double-tap the right or left part of the screen to fast forward or backward the video by 10 seconds. You can add videos from the Files app, any cloud storage or even your computer. Choose where to import the files from.To add your videos, tap the purple plus button at the bottom right.mkv, and other video formats on your iPhone: flv.ĭownload Documents for free, and let's get started! How to play. Documents is the best iPhone video player, file manager, and downloader which supports numerous file formats for videos. The built-in apps like Photos and Files just won't play such a video.ĭon't give up! Our free Documents app can play all your favorite movies. But if you've just downloaded a movie from the web, it's likely saved in either. Wondering why videos won't play on your iPhone? Chances are that your device doesn't support the file format of the video you want to watch.