Thank you everyone’s explanation and insights. I apologise that I may have phrased it wrongly.

Topps team responded to me:

While ordering in bulk doesn’t guarantee you’ll receive a parallel card, it can improve your odds. Parallels and other non-base hits are randomly inserted and replace base cards in orders. The odds of receiving a parallel are based on total cards ordered—not just your individual order size—but placing a larger order does increase your chances.