There 5 places in China where you can get visa to Vietnam: Beijing (VN embassy), Guangzhou (general consulate) Nanning (general consulate) and Hong Kong and Kunming.
The normal process will take 3-5 working days and cost 400 RMB (~60 USD), if you wish to get it same day, the fee may be doubled. Passport and passport photos are required to process your visa.
You may also get a apply visa on arrival to Vietnam. However, this method is applicable to air travel only. Our service cost is only 25$ US for one application.
This video tutorial will show you how to apply for a visa-on-arrival to Vietnam, the process involves quite a few steps that must be completed before you can pick up your visa at Vietnam airport.