Here, spelled out pretty simply:
About IATF
The IATF is an “ad hoc” group of automotive manufacturers and their respective National Automotive Industry Associations, formed to provide improved quality products to automotive customers worldwide. Specifically, the purposes for which the IATF was established are:
- To develop a consensus regarding international fundamental quality system requirements, primarily for the participating companies’ direct suppliers of production materials, product or service parts or finishing services (e.g. heat treating, painting and plating). These requirements will also be available for other interested parties in the automotive industry.
- To develop policies and procedures for the common IATF third party registration scheme to ensure consistency worldwide.
- To provide appropriate training to support IATF 16949 requirements and the IATF registration scheme.
- To establish formal liaisons with appropriate bodies to support IATF objectives.
IATF members include the following vehicle manufacturers: BMW Group, Ford Motor Company, Geely Holding Group, General Motors, IVECO Group, Jaguar Land Rover (JLR) Limited, Mercedes-Benz Group AG, Renault Group, Stellantis (ex FCA), Stellantis (ex PSA), Volkswagen AG and their respective National Automotive Industry Associations – AIAG (U.S.), ANFIA (Italy), FIEV (France), SMMT (U.K.) and VDA (Germany).
https://www.iatfglobaloversight.org/about-iatf/
So yeah. Volkswagen is part of a governing body that sets the standards that factories have to follow to be certified.
The factory I reached out to and bought directly from, JHY/Yuhuan Huayang Machinery Co. LTD (scary Chinese name, I know) is IATF certified.
View attachment 292594
https://iatf-customerportal.org/site (you can search for their certificate number, 466984)
That means that factory, follows standards that are set by a governing body that Volkswagen, is part of.