The first way, All you have to do is just to fill in online form: https://www.vietnamvisaform.com/apply-vietnam-visa
Other way, Visit Vietnamese embassy in Bang Kok
83/1 Wireless Road, Lumpini, Pathumwan, Bangkok 10330
+ Tel. 66 (0) 2 251 5836-8
+ Fax. 66 (0) 2 251 7203
Office hours: Monday – Friday: 08.00-11.30 Hrs. and 13.30-16.30 Hrs.
You are required to provide 1-2 passport size photos and the cost was about 1500 Baht. Normal process takes around 2-3 days, if you need an express one (1 working day), then you have to pay a little bit more.

