It's hard to tell what you want to do.
In general, the camera captures RAW data always. The RAW data is then either delivered as a RAW file, or converted into a JPG using in-camera settings, and delivered that way, or both. In almost all cases, the camera makes a low quality JPG using the in-camera settings no matter what, and this is used to supply the image that you review on the LCD on the back of your camera.
If your question involves retouching JPGs in-camera post capture, than I'm not sure what you're trying to do, and perhaps you could explain it a bit.