Use Form 587 to allocate California source payments and determine if withholding is required. , room, PO box, or PMB no.) City (If you have a foreign address, see instructions.) City (If you have a foreign address, see instructions.).Payees must complete FTB Form 590, Withholding Exemption Certificate, to certify their status. The W8BEN and W8BENE forms are essential for foreign independent contractors and businesses. Discover essential steps for safely paying international contractors. Our guide simplifies compliance, currency, payment methods, contracts, and more. In this lesson we will mine withholding tax, determine who is required to withhold, review the proper withholding forms.