Thanks for your question!
It is informed that E-visa is not available for Bangladeshi citizens. However, you can apply online on our website for visa on arrival but we JUST can help you to process 1 month single tourist visa and the service fee is $150US/person (not including $25US stamping fee at Vietnam airport). However, the Vietnam Immigration does not process 1 month visa for full 30 days, they just base on your ticket to process visa (maximum 25 days). The processing will take 7 – 10 working days
And you can apply online at this link: https://www.vietnam-evisa.org/apply-visa.html
In addition, after finishing payment online, please send us your passport scan + hotel booking + return ticket via email. Without those documents, we can not process visa for you
If you want to stay longer, please go to the Vietnam Embassy to apply visa