Most visitors to Vietnam need a visa to enter the country. Visas are exempted for the citizens of the countries, which have signed a bilateral or unilateral visa exemption agreement with Vietnam, tourist visa may be valid for 15 to 30 days.

Procedure for applying visa:

Tourist visa can only be obtained in Vietnamese embassies, consulates abroad. Otherwise, you can get a visa at the border gates if you are invitees of some Vietnamese competent organs or you are travelling on a package tour organized by Vietnamese travel companies. To apply for a visa, the requirements are as follows:

Entry permit form (which can vary from one Vietnamese embassies or consulate abroad to another).
Two photos (4cmx6cm or 3cmx4cm)
Original passport
Visa fee.
You should send your application and photos to a Vietnamese embassy or consulate abroad, which is most convenient to you. On your requirement, the reply will be returned by post (you must provide stamped envelopes with your name and address).

It is easier to get your visa from a Vietnamese travel agency. The necessary information to the travel agency include:

Full name
Birthday and place of birth
Nationality
Job
Number of your passport
Entry and exit dates
Country you plan to receive your entry visa from the Vietnamese embassies or consulates
Visa extension: this service is available at all travel agencies

Visa exemption:

Vietnamese people that hold foreign passports and foreigners who are their husbands, wives and children are exempt from visa requirements to enter Vietnam but are allowed to stay for no more than 90 days. In order to be granted a visa exemption certificates at the Vietnamese representative offices abroad, overseas Vietnamese need these items:

A foreign-issued permanent residence certificate (PRC) with the validity of at least six months since the date of entrance.
Visa exemption paper (VEP) is granted by Vietnamese appropriate authorities
Those who expect to stay more than 90 days must apply for a visa according to current stipulations before their entrance.

Bilateral visa exemption agreement

Citizens of Thailand, Philippines, Malaysia, Singapore, Indonesia and Laos holding valid passports are exempt from visa requirements but are allowed to stay for no more than 30 days.
Citizens of China, Bulgaria, Kyrgyzstan, Romania and North Korea holding valid ordinary passports for official affair and citizens of 52 countries holding valid diplomatic or official passports are exempt from visa requirements.

Unilateral visa exemption

Officials from the ASEAN secretariat holding different kinds of passports are exempt from visa requirements but are allowed to stay for no more than 30 days.
Citizens of Sweden, Norway, Denmark, Finland, Japan and South Korea holding different kinds of passports are exempt from visa requirements and are allowed to stay for no more than 15 days.