Q.What do I do if I do not have another cactus stock to graft my moon cactus onto?
I am new to the Moon Cactus and I am wondering if it is required to graft the cactus? If so how often?

Certified GKH Gardening Expert
If you have purchased a moon cactus, then you will already have the grafted rootstock. That is the green cactus on bottom.
If you would like to graft your own, then you can use a dragon fruit cactus as your rootstock.
This article will help you to graft cacti: https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/grafting-cactus-plants.htm
This article will help you with the care of the moon cactus: https://www.gardeningknowhow.com/ornamental/cacti-succulents/moon-cactus/care-of-moon-cactus.htm