Vietnam government requires that citizens of most foreign countries obtain a visa to enter.  The types and categories differ according to the purpose of visit, length of stay and respective arrangement with the country of the foreign national.  Below are different types of visas issued by the Consulate of Vietnam.
Tourist Visa 
A Vietnam tourist visa is issued only to applicants entering the country for the purpose of tourism, or for a private visit.  The Vietnam tourist visa is granted on the basis that the holder return to their country of residence upon the expiry of the visa, and will not engage in employment while visiting in Vietnam.  The single entry Tourist Visa for Vietnam is ordinarily issued for a time of one month however in the event that you wish to stay longer in Vietnam you may request a one month extension. You can apply for a three month single entry visitor visa as well as 1 and 3 month multiple entry visas on the off chance that you wish visit neighboring nations like Cambodia, China, Laos and so on and return to Vietnam.
Business Visa  
The Vietnam business visa grants holders the right to attend meetings, conferences and other business-related activities. However, the holder of the visa will not engage in employment in any capacity while in Vietnam.

Diplomatic and Official visas
Diplomatic and Official visas requires you to present an official letter from the government, worldwide associations, consulates or other certify associations in your nation. Ordinarily there is no application fee charged for such visa unless it is agreed upon between the concerned nations.
Student visa
Student Visa can be obtained easily if the prospective student has already enrolled in a college or university in Vietnam. In any case, it is acceptable to enter Vietnam on a visitor/tourist visa, then complete your enrollment in a Vietnamese college or university course and then apply for an student visa.  Once you have enrolled in the college or university you must have your visa status through the immigration division.
Crew Visa
Crew visas are reserved for employee of airlines or cruise ships.

• pilot or flight attendant on a commercial airplane
• captain, engineer, or deckhand on a sea vessel
• lifeguard, cook, waiter, beautician, or other service staff on a cruise ship
• trainee on board a training vessel

Visa Extension
In the case you wish to extend your visit in Vietnam as a tourist you can easily get your visa extended to one more month through immigration department. The immigration department will request a Visa extension fee of $10. The extension protocol in major cities like Hanoi, HCMC, Hue and Danang tends to operate smoother because there are the major attraction for the tourists. The Visa extension process for business and Student Visa works in similar ways. However in each case you have to demonstrate a good reason as to why would want an extension.