Vietnam visa basically has 4 types. Following information provides you with some overview about types of Vietnam visa.
Tourist visa: A tourist visa is usually valid for 1 month, allowing single or multiple entry.
Business Visa: A business visa is usually valid for 3 months, allowing single or multiple entry and the right to work. Getting a business visa has now become cheap and easy. There is no difference between procedures to apply for business or tourist Vietnam visa.
Student visa: A student visa is usually arranged after your arrival. In order to get student visa for Vietnam, you are sugested to apply for a tourist visa to enter Vietnam, enroll in a Vietnamese language course and then apply at the local immigration department for changing your Vietnam tourist visa to Vietnam student visa. In reality, the easiest way to do it is to contact a travel company and have them assist you with the visa application.
Transit visa (or visa for city visiting): The maximum duration of this type of visa is 5 days. The Immigration Department will issue transit visa for groups in tour, accompanied with a tour guide. The group must have exact itinerary and have guarantee of a travel agency which organizing the tour.