You can enter and exit Vietnam through any 28 designated international checkpoints.
E-Visa holders can enter and exit Vietnam through any checkpoint in checkpoints.
You can check allowed port list on : Port List.
EVisa holders must show the eVisa copy in printed A4 Paper and valid passport at the time of immigration checkpoint.
The validity period of eVisa active from the date mentioned in your e-Visa. You can enter any date range within the mentioned period.
Applicant cannot visit Vietnam using approved eVisa. Reapply again.
Reapply again with fresh travel date, once it processed, then previous eVisa will be invalid.