I know about a Paypal feature to charge taxes. But You must pay taxes where you receives the payments or where the services is paid (mainly USA)?
There is no general answer to that question. Regulations differ across the world and even within the same country or economic zone. Ask your accountant, tax lawyer or someone with experience.
In the EU, depending on the size of the company, you pay no sales tax, your country's sales tax or the tax rate of client's country of residence. For shipments outside the EU, you may not need to charge a sales tax at all.