Visa Exemption

Hello,

I am traveling with my boyfriend to Vietnam in mid may. We will only stay there for 13 days and even we are aware that there is a Visa exemption for less than 15 days, I would like to make sure if there is anything else that we have to do in advance before flying to Vietnam.
Do we need any document? or we can directly cross arrival customs just with our passport ?

Thanks a lot for your help.
Regards.
Anna.