Being a Botswana passport holder, you first of all should be aware that you need a valid visa for your every trip to Vietnam, regardless of where you are, how long you are staying in the country and purpose of your visit (tourist or business).
Visa on arrival (VOA) is considered a convenient option for Botswana travelers to get a valid tourist/business visa for Vietnam as it is completely applied online with an internet-connected device without any document. It is available for both tourists and business travelers with long-term stay.
How to get Vietnam visa on arrival for Botswana citizens in Australia?
Here is full picture about Vietnam visa for Botswana citizens. However, it may be changed from time to time.