You can apply Vietnam Visa through Filling Form Online or through Local Embassy. Online procedure is fast way to get Vietnam Visa. You need to fill a online form, submit online fees, after 2 working days you get approval on your Email. You need two recent, identical, 2 passport type photographs with visa approval letter, along with your passport.
When you arrived the Destination Airport, show your Visa Approval letter with Photographs, stamping fee with entry-exit form at immigration office. There you get your Visa after all your legal clearance.