Thanks for your concern,
Vietnam offers 15-day visa exemptions with single entry for visitors from THE UK However, their passports should have at least six months of validity upon the date of arrival to meet airlines’
requirements, and their arrival date is NOT within 30 days from their last exit date with visa exemption.
Otherwise, they will need a Vietnam visa.
For Brazilian please apply for visa at my link https://www.vietnam-evisa.org/apply-visa.html
Apply visa online, You will get visa stamp on the passport upon arrival, All you need to do is fill your
information in the form and make payment online.
After that, we will send You the approval letter via email, please print it out to board the plane and use
it to get visa stamp on the passport upon arrival.
Stepfanno Tran (Mr. )