To visit Vietnam you need to apply for either Tourist Visa, Business Visa or Work Visa.
Tourist Visa:- For Travelling and Exploring you need a Tourist Visa.
Business Visa:- This type of Visa you required, to do some Business in Vietnam.
Work Visa is required, if you are planning to do, Jobs/Work in Vietnam.
For more info:-
www.vietnammyvisa.org/apply-online