Lightroom is a tremendous powerhouse of a tool, and as you learn it you'll come to appreciate its many features. One of the most critical is the ability to work with the full range of tones and colors available in a RAW file.
The short answer to the question is "Yes." Lightroom adjustments and Photomorphis presets will work with most image formats including RAW and JPEG.
A more complete answer is that the results of our presets on RAW and JPEG versions of an image will not look the same due to the smaller tone and color gamuts in the JPEG file. The preset applied to a JPEG file will miss much of the finesse and subtleties programed into the preset which are generated from (and for) a RAW image file.
As you can probably tell, our recommendation would be to use RAW files where you can for much higher quality results from your processing. That said, you'll have just as much fun exploring the possibilities of our presets with any images you have in JPEG format.