Many people keep asking how many types of Viet Nam is available, but it is hard to give the correct answer since it depends on what criteria you are mentioning. So kindly look at the below writing and find your answer or reference.
1. Address to apply and get the visa

he traditional way to get the Vietnam visa is to go to Embassy or Consulate in your country. It is convenient for those living near the embassy/consulate and having free time during working hours. Another option, in the technical world, is to apply online to get the visa on arrival using your computer connected with the Internet and you will get the visa stamp upon the arrival airport in Viet Nam. Each way has its own advantages and the choice totally depends on your condition.
2. Duration of stay

At the moment, there are 2 options: 1 month and 3 months visa. You should choose the visa that covers your longest stay in Viet Nam. In the past, 6 months visa was officially available for your choice but it is no longer valid. If your plan lasts more than 3 months living continuously in Viet Nam, your unique solution is to apply a 3 months visa and then extend it when it reaches the expiration date, but you should find out a travel agency which can support you on this issue and make sure it can be done.
3. Purpose of entry

Theoretically, there are 2 types of visa regarding purpose of visiting Viet Nam. The tourism visa is granted for 1 month only while the businessman is permitted to get 3 months visa. However, the applicants are normally NOT required to show supporting document to prove the real purpose of the trip when applying visa, except for some special cases. Therefore, you can absolutely apply 3 months business visa for your trip in Viet Nam more than 1 month and do not worry about the conflict.
4. Where you enter Viet Nam

Except for visa at the embassy which is acceptable at all borders in Viet Nam, when you decide to apply visa online or with travel agencies, you should state clearly what transportation means you will use. For example, visa on arrival is for those fly to Viet Nam only. If you enter by sea or by land, you should know that just only some agencies are authorized to support these visas; then ask them before apply. Choose wrong type of visa can push you to the trouble.
Hope that all above information can satisfy your questions on types of Vietnam visas. The most important thing you should care is how long you stay in Viet Nam and transportation to arrive Viet Nam.

Sources: http://trulyvietnam.com/