Compensation for services performed abroad is foreign source income. For audit purposes, the place where the services are performed should be indicated in the agreement with the individual. It is not sufficient that the location where the services performed is indicated on the invoice since this is considered by the IRS to be a self-serving statement.
If you have a Form W-8BEN as a certificate of foreign status (no TIN required) from the service provider and the location of the services is documented, you do not have to withhold U.S. tax on the compensation payments. You are also not required to report on the income. You may, however, report the income on a Form 1042-S under Exemption Code 03 (foreign source income).
Even without the Form W-8BEN, you are not required to withhold or report on compensation for services performed abroad if you have no actual knowledge or no reason to know that the recipient of the service provider is a either a U.S. citizen or resident alien or that the income was effectively connected to the conduct of a U.S. trade or business.
You may have withholding or reporting obligations, or both, in the country where the services are provided.