Many photographers know that you can shoot in black and white by using a setting called black and white or monochrome. The assumption is that this is just for JPEG, so RAW shooters think this is not useful. RAW can only be shot in color.
There is a trick to shooting in black and white that will gain you more control, let you use RAW, and help you learn this medium better. All DSLRs and DSLMs (digital single lens mirrorless) will allow you to shoot RAW + JPEG. This gives you a black-and-white JPEG image and a color RAW file. Everything you shoot will now appear as black and white on your camera’s LCD so you can actually see and control the black-and-white image as you shoot.
RAW cannot be anything except color. If you tell your camera to shoot in black and white but only shoot RAW, you will see a black-and-white LCD image, but when you open the file in software that works with your file, such as Lightroom or Camera Raw, it might first show up as black-and-white, but it will change to color as that software creates its own preview from the file (an exception may be the RAW software made by the camera manufacturer, though it can be changed to color).
This allows you to compare your color and black-and-white images back on your computer. In addition, you have that RAW file that can be translated to black and white later if you need more flexibility or control as you adjust the photo.
Shoot in black and white with RAW + JPEG and you will get both a color and black-and-white image.
If you use Lightroom, you will be disappointed to see your images first appear as black and white then change to color. You have to tell Lightroom to recognize both RAW and JPEG in Preferences before you import the shots. Go to Preferences under Edit menu (PC) or the Lightroom menu (Mac). In the first tab, generally, you will find a box that says, Import Options. Check, "Treat JPEG files next to raw files as separate photos." Both RAW and JPEG will now show up in Lightroom, which is very cool because you now see the photo both in color and black and white. Turn the "Treat JPEG files next to raw files as separate photos" off when you are done importing.