Do I need to print the Vietnam arrival card confirmation or is a screenshot enough?

A screenshot or saved copy on your phone is normally enough, because immigration scans the QR code on arrival. The portal also sends a confirmation with a file number that you can show.

Printing a copy is still a sensible backup. If your phone battery dies or the screen is cracked, a paper sheet saves you from refiling in a queue. Airport Wi-Fi may be slow, so having the QR code stored offline helps.

Save the image to your photo album, take a second screenshot of the file number, and keep the confirmation email. You can reopen the form at prearrival.immigration.gov.vn if something goes wrong.

The same logic applies to your e-visa. Airlines can ask to see it at check-in, so keep a printed copy as well. If you still need the visa, you can apply for a Vietnam e-visa online and download the PDF by email.