Before coming to Photoshop let us see what is raw, where you find it, and why it is different from other formats. Raw is a camera format, you can usually find it in DSLR camera or these days in bridge cameras also.
Raw can be defined in 3 words that is “as it is” as you got your photos as it is without any processing or compression. Usually it generate much heavier size files that jpeg.
Most of the time people are confused between Raw and JPEG format.
Actually jpeg is a compressed format, when you capture a photo with jpeg format, your camera process the colors according to its own brain and compress photo in jpeg format. But after that you don’t have full control on image to have your desired adjustment.
But in case of raw images you have much better control over image as this time camera didn’t used its mechanical brain to process your lovely photos. You can surely ask us question or suggest something in the comment section given below, Each and every Comment will be Appreciated and Answered! Cheers!