Can I put a spin the wheel popup on my ordering page before people order?

Yes. Under Marketing → Spin the wheel popup, tick Show the wheel, choose the look, whether it appears as a window or a sheet from the bottom, when it shows, and fill the segments: each gives nothing, a percentage off, an amount off, a free item or a gift card code, with a minimum order and a chance in percent. The visitor types their WhatsApp number and spins, once per number every so many days. You decide who wins before the chances are used: pause all wins, cap the wins per day, or let only every Nth spin win. A won code is applied at checkout once the cart reaches the minimum order. The Promotions & marketing tab in the docs has the guide.