Example for self-reporting and independent “On-site visits” and "Audits"
ADT Group Holdings Pty Ltd, Pg. 9
“Suppliers are required to complete a pre-audit questionnaire and undergo either an annual internal audit conducted by our in-country compliance teams or provide a reputable third-party audit conducted in the past 12 months.
“During the reporting period, we conducted 59 audits (internal and third party), on both an announced and unannounced basis.”
The mention of announce and unannounced infers that these are onsite audits.