Regarding your question, we would like to inform you that Afghan passport holders are required a visa for visiting Vietnam, therefore you need to apply for a visa for your visit to Vietnam.
There’re 3 options to get a visa for visiting Vietnam as below, you may select one of them to get a visa for your trip:
Option 1: Apply for an e-visa of Vietnam
From Jan 2017, the government of Vietnam has launched an official website for e-visa of Vietnam: www.evisa.immigration.gov.vn, however, we checked and found that citizens of Afghanistan are not eligible to apply for an e-visa. Therefore, please choose option 2 or 3 to get a visa for Vietnam.
Option 2: Request for getting visa on arrival with support from a company in Vietnam
Visa On Arrival (VOA) is one of the several visa types issued by the Vietnamese Immigration Department to foreigners intending to enter the country.
If you want to pick up your visa on arrival at international airports of Vietnam, you should apply online through a website for Vietnam visa or contact your travel agent in Vietnam to ask for a visa approval letter from Vietnam Immigration Department.
Then upon arrival at the international airports of Vietnam, you are required to show the visa approval letter to get visa stamped on your passport.
Please note that unlike visa on arrival of some countries in the world, in order to get visa on arrival of Vietnam, you must have a visa approval letter from the Immigration Department of Vietnam which allows to pick up your visa on arrival at the international airport of Vietnam.
Option 3: Apply for a visa at the embassy of Vietnam
There is no embassy of Vietnam in Afghanistan, therefore you should find the location of the embassy of Vietnam close to you to apply for a visa, we can suggest the embassy of Vietnam in countries close to Afghanistan such as : China, Iran, Pakistan or Uzbekistan.