Yes, Indian passport holders must have a valid visa to visit Vietnam. They can easily apply for an e-visa online without visiting an embassy or consulate.

Yes, Indian citizens can apply for a multiple-entry Vietnam visa through the government website or Atlys. A multiple-entry Vietnam e-visa is valid for 90 days and allows you to stay in the country for up to 90 days.

Yes, you must print out your e-visa before travelling to Vietnam, as you will need to present a physical copy when you land at the airport.

No, entering on the exact date is not mandatory. You can enter Vietnam on any date between the arrival date and exit date stated on your e-visa for Vietnam. Please note that earlier entry is also not allowed.

No, e-visa holders can enter Vietnam only through 42 designated ports (land/sea/air). 
Some of the major international e-visa entry ports are Tan Son Nhat Int. Airport (Ho Chi Minh City), Noi Bai Int. Airport (Ha Noi), Cat Bi Int Airport (Hai Phong), Da Nang International Airport, and Cam Ranh Int Airport (Khanh Hoa). 

No, the Vietnam e-visa is generally not rejected at the immigration checkpoint. 

However, you might be refused entry in cases where:

• The validity of your Vietnam visa has expired. 
• A change in your situation goes against the eligibility criteria for issuing a Vietnam visa. For example, your passport is no longer valid for 6 months.