I am trying to set up my tax information. I am a US citizen currently living in Vietnam. I have several questions.
1. Do I need to have set up a business entity before working on Upwork? This is not clear at all; the tax information page seems to want a 'business name'. The site filled in my username...?
2. I am not sure what address we will be using on our taxes. We have a residence in the US that I assumed we would use. Mail here is unpredictable and I'm not sure about using our Vietnam address. Where can I find more information about this?
Income taxes are generally based on location.
If you are living permanently in Vietnam, you need to pay taxes there. (Your upwork location also needs to be Vietnam.) It is possible you also have to pay taxes in the US, but that could be made easier if there is a double taxation treaty in place between the countries.
In any case, you will need to consult with tax lawyers in both countries.