My Nikon B700 pics are coming out black without flash?

Prior to recently everything was working fine. But now every time I take a pic without flash it comes out dark. You can't see anything.

D700? Reset (press Qual and +/- at the same time until the LCD blinks). Set to Auto mode, Auto white balance, Auto ISO, AF on, and make sure exposure compensation is at zero. Look for a brightly colored car parked under the sun and take a photo of it from around 10 feet without flash. If the photo comes out dark then the iris of the lens might be stuck to smallest (probably due to a damaged aperture motor error). If this is the case, you will have to bring the camera and lens to the service center.

If the picture comes out correctly, that means you don't know what you're doing. Leave the camera at Auto all the time then, including Flash mode.

First you need to learn how to balance the ISO, shutter speed and lens aperture using the cameras light meter

However, you need to spend time learning the fundamentals of photography, lighting and composition over the next year or so

I don't know

Learn the basics of exposure.

Refer to this link - https://maini.live/2017/03/05/basics-of-exposure/