Thank you for contacting us!
We are sorry to inform you that Vietnam visa on arrival is just applicable for air travelers. In your case, you are suggested to get a visa at the nearest Vietnam Embassy/ Consulate where you are staying or living.
You need to take your passport, a passport-sized photo, and cash in person to the Consulate, where you will be interviewed about the purpose of your visit. You must also pay the stamping fee and wait in a few days to get the visa. Please note that the application procedures and fees may vary among countries and embassies/consulates.
Hope this helps you.