A compliant AML program has four or five pillars: written policies, a designated compliance officer, ongoing training, independent testing, and risk-based customer due diligence. Broker-dealers, futures merchants, banks and increasingly crypto firms all carry the obligation.
For a trader the visible parts are onboarding identity checks under customer-identification-program, questions about source-of-funds when large deposits arrive, and occasional account freezes while a review is done. The firm is generally forbidden from telling you a report was filed.
Enforcement is severe and does not require any money laundering to have occurred. Failing to maintain the program is the violation, which is why firms err heavily toward friction.
Related: bank-secrecy-act, customer-identification-program, suspicious-activity-report, kyc, sanctions-screening