Hi. I would like to go to YIWU for the purpose of trade. Would i need more than 1 visa?

I would have to go to Shanghai and then to YIWU. Also apart from the invitation are there any other requirments that i would need? in 1 of the previous question and answers i saw you list 1 of the requirements as round trip tickets and hotel reservation. Does this mean that i must purchase tickets before application? Looking forward to a reply, thank you.