[UPDATED ON 15/11/2020]
In Vietnam when you are a Foreigner, it is easy to open and office to host your activities but opening a shop selling to the population is more complicated. It requires an additional authorization for the headquarter that is called “Giấy phép bán lẻ” and one “Giấy phép lập cơ sở bán lẻ đối với công ty có vốn đầu tư nước ngoài” for each shop you will open!
For instance if you open a coffee shop selling products to be consume on site, no sub-license is required but if you sell coffee in your coffee shop (the beans or the powder), 2 sub-licenses will be required, one for the main office and one for each location/shop.
It is somehow costly to request for one if you are a foreigner. Therefore you should seek proper advice when open a shop!