Actually you do, depending on the location (and thus local laws). You definitely don't get an employment contract, and that means that e.g. in the whole EU, you

Actually you do, depending on the location (and thus local laws). You definitely don't get an employment contract, and that means that e.g. in the whole EU, you need a business license (self employment or a company); some EU countries allow that from 16 and some (most) from 18; it's illegal to make an invoice if you don't have a license, and Upwork requires you to do so. You're right that I could've worded that better, that's what I meant with the last part of my comment.