US tax-return preparers who send return information to a preparer outside the United States generally need to obtain the taxpayer's consent first. The rules sit in the Treasury regulations under section 7216 of the Internal Revenue Code, and the exact consent wording and conditions matter.
Settle these before the first file moves
Confirm with your compliance lead or adviser what consent your clients must sign and how long you must retain it. Decide which data is truly needed by the offshore team and whether it can be redacted. Put an NDA and a written service agreement in place. Agree which software and file-sharing channel will be used, and who has access.
Keep review where it belongs
Responsibility for the return stays with the signing preparer. A documented review step, with a named reviewer on your side, protects both the client and the firm.
Start small
A short pilot on a few live files shows how accurate the work is and how smoothly communication runs, before any commitment. This article is general information, not legal or tax advice. Please confirm current requirements with your own adviser.