Why my laptop screen is not open

@divyasingla you are not giving us much to work with here. Don't make us guess! If you are serious about trying to fix your laptop, you need to give us more detailed information.

For now,and from what I "read between the lines" it sounds like your LCD screen is not working. If everything else is working except your screen, connect an external monitor. If that works you know the issue is between your screen, your display cable or your display connector. If an external monitor does not work either, the issue is related to your GPU.