could you experienced freelancers help me here? I'm a freelancer working from Brasil, and I will spend 3 months in Europe. Do I have to pay any extra taxes for my projects (upwork)? What about my payment, can it still be done by paypal? Thank you!
There shouldn't be a problem. Upwork delivers payment to your PayPal account. It doesn't matter where you are.
The only way this would be an issue is if the country you're visiting doesn't allow you to use PayPal for spending money (with the PayPal card) you will still be receiving your normal funds through your payment regardless.
Upwork takes a flat % (20, 10, or 5 depending on contract worth) and you pay income tax based on where you are a citizen of. You're not an EU citizen so you don't owe a foreign government part of your income.