Please Vietnam does NOT have any normal person would call an E-Visa, as in electronic Visa. Vietnam has a Visa on Arrival system, which means yo pay some money and get a letter saying you can get aVisa upon arrival in Vietnam by paying $25US and waiting on line. When I went thru the airport two weeks ago, there were 100+ people waiting for their VOA.

Anyone who needs a visa, you are far better off going in person or sending your passport to the Vietnamese consulate in their country.
Visa | Embassy of the Socialist Republic of Vietnam in the United States

I got my one year multiple entry tourist visa in 15 minutes in New York.

In the above link, they provide this warning:
"* Online visa: As the Embassy cannot confirm the reliability of online visa services offered by many companies on the Internet, it is strongly recommended that travelers obtain suitable visas prior to their trip to Viet Nam. There have been reported cases of fraudulence and personal data theft when applying for online visa and cases of entry refusal on arrival when these types of online visas are applied through un-recognized websites with no connection to the Embassy. The Embassy cannot verify the validity of such visas and cannot provide assistance to travelers in case they are refused of entry while using these types of visas. In order to avoid any risk of personal data theft or losses through fraudulent use of credit/debit cards, travelers are strongly recommended not to provide personal information on untrusted websites."