That will depend. If it is music that is just within a specific app, then you will have to refer to that apps information.
If it is not app specific, then you can go into each specific file and seek to move them. One at a time.
You can also plug your tablet into a computer, move all the music over to a folder on the computer, organize it how you want (names/folders/etc.) and then copy it all back over to the SD card rather than the tablets internal storage. I say copy back over (rather than move) because it is always best to save copies of things off of a tablet or phone. They are to easily lost, stolen, deleted, etc. otherwise. You may want to also do that with any photos.