There is a 10% withholding tax on any services provided in PR, including professional services such as plumbers, carpenters, lawyers, etc.Â
Your client will withhold the 10% on your invoice if he follows the rules and pays his taxes; otherwise, he cannot deduct your services from his company taxes. He needs your SSN to do this. You get credit for the withholding when you file taxes on the money you earn in PR. Â
Unsurprisingly, many do work under the table, which can have serious consequences.