When you select a file from the library that you want to use in distribute then default you have to type in the new file name. But you can also get distribute to pull the file name from a Meta tag. This is handy if you like to keep you original file name in the library but when you distribute the file then use the commercial ID from Meta tags. That way you can keep you original file name in the library and don’t have to rename them, so you can have as many file names as you like.
Go to the preferences menu under "Preset" and scroll down a bit to you see the Distribute name preset and then type in the name of the field from Meta Input that you would like to use as file name, then Distribute will use this as the new file name.