Dear Bibek Tamrakar
Thanks for your question. You can apply for visa on arrival with us.
Apply visa online, you will get visa stamp on the passport upon arrival:
Step 1: You can follow my link to apply for visa on arrival https://www.vietnam-evisa.org/apply-visa.html without any documents. All you need to do is fill your information in the form and make payment online.
Step 2: We will send you the approval letter via email, please print it out to board the plane and use it to get visa stamp on the passport upon arrival.
In case you want to apply for visa stamp before you arrive, please apply with VIETNAM embassy near your country living
Thanks for choosing our service.