Hi Aayushi, visiting Taj Mahal during full-moon is a must when visiting Agra. To witness this beautiful sight, you need to purchase the ticket a day prior. I will suggest you to inquire about the same here: https://www.tajmahal.gov.in/nightview.html. This is the official govt portal for Taj Mahal. The tickets are available a day before from 10.00 A.M. to 6.00 P.M. Price for adults - INR 700, Kids - INR 500.