My friend, there are HUNDREDS of posts clearly stating all the documents submitted. Use the Facebook lens for the research and type in the embassy you will apply at (ho chi Minh or Hanoi) and read those posts. Do your homework and you'll sort out everything you need.
Some embassies might approve everything online, some might require an interview in person cuz they have doubts, some seem requiring an interview to anyone who applies. I got asked for an interview when I applied so I had to physically go to the embassy.
if u have no intentions to live in Thailand for a long term in the near future, you could just come in without any visa. U do 60 days, una border bounce and 60 more days. You can eventually extend both 60days up to 90 if you pay 1900baht at the immigration.