For now you can only add items by their numeric ID.
You can find a nice table of all the item ids here.
It's the number in the first column.
This webpage's source code is available at https://github.com/RSCPlus/rsc-bank-organizer.
It was originally created by The Legend of Brian in 2016 to plan how to organize his bank, but it has been expanded here to help sort everyone's bank, automatically.
Brian's layout has been left mostly intact above, but without a duplicate Super Defense potion, the addition of Marrentill, and goldsmithing gauntlets instead of cooking gauntlets. ☺