Authored by Sabih Khan, Apple's senior vice president of operations, the letter details changes that Apple has made to protect its supply chain partners, such as strict adherence to social distancing, limiting density, and health screenings.
PDF: https://www.apple.com/supplier-responsibility/pdf/Apple_SR_2020_Progress_Report.pdf
Source: https://techcrunch.com/2020/05/14/apple-operations-svp-details-supply-chain-safety-changes-due-to-covid-19/
More: https://www.macrumors.com/2020/05/14/apple-2020-supplier-responsibility-report/