OnSong works best with plain text (.txt) files. With text files, you can change the text properties, such as font, size, color, and even transpose into different keys if OnSong recognizes your text file as a Chorpro format.
But what if all your lyrics are in Word (.doc) files? You can save Word files as text files from within Word, but if you have dozens - hundreds - thousands of these files, then that quickly becomes a major headache. What you need is a batch file converter.
Here are two programs that will convert multiple Word (.doc) files into Text (.txt) files in a jiffy.