Visa is NOT required for citizens of Denmark to stay in Vietnam for less than 15 days. If you intend to stay in Vietnam for longer than 15 days, then you have to apply for a visa and may have 2 options: Visit Vietnam embassy in Denmark (Copenhagen) or apply for a visa on arrival to Vietnam from Denmark online. Danish citizens may apply for both tourist and business visa to Vietnam for the stay of 1 to 6 months from Denmark. Please check this link for visa fee for Danish citizens.

All the information for getting a visa from Vietnam embassy in Denmark can be found here: www.vietnamemb.dk