That you have to submit to the Immigration Officer when entering Vietnam.
Vietnamese Visa Application Form (The entry and exit form) is an important document.
In case you have not got the Vietnamese visa application form from any source yet, you can take one at the airport upon your arrival to fill out with your information.
However, it may take you 5 to 10 minutes to fill out. So we highly recommend you to download and fill it out before departing for Vietnam for time saving.