According to Decree No. 21/2001/ND-CP of May 28, 2001, detailing the implementation of the Ordinance on Entry, Exit and Residence of Foreigners in Vietnam, the procedures for foreigners to apply for visa for entry to work at Vietnamese enterprises are as follows:
In case of invitation
Foreigners being invited by employing Vietnamese enterprises will be granted single or multiple visas, which are valid for no more than 6 months.
Enterprises that invite foreigners into Vietnam shall send written requests to the Immigration Department of the Ministry of Public Security.
The Immigration Department shall notify its approval to Vietnamese diplomatic missions or consulates in foreign countries so that the latter grant visas to invited foreigners within five working days after receiving the written notices or requests. If it detects that the invited foreigners fall into cases not yet permitted for entry, the Immigration Department shall inform the inviting enterprises thereof.
Enterprises that wish to have visas granted to foreigners at Vietnam’s international border gates shall send written requests to the Immigration Department. In case of application for visa grant at border gates for urgent reasons, written requests therefor must be filed at least 12 hours before the invited foreigners arrive at the border gates.
After receiving written replies from the Immigration Department, the enterprises that have invited foreigners to Vietnam shall notify such foreigners to file their applications and photos and receive visas at overseas-based Vietnamese diplomatic missions or consulates. For foreigners to be granted visas at Vietnam’s international border gates, the inviting enterprises shall notify them to file their applications and photos and receive visas at the immigration offices at such border gates.
Vietnamese diplomatic missions or consulates in foreign countries shall base themselves on notices of the Immigration Department under the Ministry of Public Security to grant visas to foreigners upon receiving their visa applications and photos.
In case of non-invitation
Foreigners applying for visas for entry into Vietnam who are not invited by Vietnamese agencies, organizations or individuals shall file their visa applications and photos to Vietnamese diplomatic missions or consulates in foreign countries for consideration and granting of visas which are valid for 15 days.
The consideration and grant of visas shall be carried out within 3 working days after the applications and photos are received.
Source: VIetnam law& Legal Forum