Is it able to pay for registering? I assume it is connected some kind of payment APP. So is it possible for guest to pay by some APP (e.g., Apple payment? ) then register?
Yes, it is possible, but not out of the box. You'd need some sort of custom plugin for this to work, and it would hook out to some sort of payment processor to handle everything. Did you have something in mind?
Um. What is payment processor.. Here we use Wechat or AliPay.. https://intl.alipay.com/ The largest mobile/online payment software/APP.