Copying music onto an SD card doesn't require any software beyond Windows 7 or 8 itself, where the fastest method is to use the Send To option in the right-click menu. If you're not sure where iTunes or Windows Media Player stores the music file you want, however, both programs provide links to any song in your library.
Right-click a song or album in your iTunes 12 library and choose Show in Windows Explorer to locate the music file on your computer. If you use Windows Media Player, follow the next step instead.
Right-click a song in your Windows Media Player 12 library and click Open file location to open the folder on your computer that contains the music file.
Plug in your SD card and then right-click the music file in the Windows folder -- not from inside iTunes or Windows Media Player. Point to Send to and choose your SD card from the list to copy the song.
To copy several songs at once, select them by clicking and dragging, or by holding Ctrl while you click on each, and then right-click any song in the selection.
Browse to a higher directory from your music folder to copy multiple albums or even your entire music library at once. For example, by default, iTunes stores all music inside the iTunes Media\Music folder, so click on iTunes Media in the address bar to find and copy the Music folder.
If you've changed the settings in iTunes or don't use iTunes, your music might be scattered across different directories on your computer. Repeat the Show in Windows Explorer or Open file location step to locate songs you can't find.
Press Windows-E on the keyboard, or click Computer on the Windows 7 Start menu, to open the Computer window and check how much free space you have on your SD card. If you need to , double-click it to see its contents.