I would like to recommend that you follow k-pi's advice. SD cards are more likely to fail than USB memory sticks or USB HDs. I keep useful information e.g. how to install a hard disk, additions I have made to the Minimal Kiosk Browser, lists of radio station URLs, working VOD sites
in text files on a USB memory stick and back them up onto a hard disc. Nothing is more frustrating than failing to remember how to do something. I have a Seagate 2 TB hard disc which is powered by one of the Raspberry Pi 3's USB ports. If you have omxplayergui you can set up a menu which will play media files (music, radio stations, videos, saved TV and radio programmes etc) wherever they are stored on the Pi.