https://wccftech.com/microsoft-begin-selling-windows-7-extended-support-plan-april-1/

We reported earlier that Microsoft will offer extended support plans to businesses who cannot upgrade all of their machines to Windows 10. The Windows maker had shared quite an expensive support plan that offers security updates to Windows 7 devices after the January 2020 end of support deadline on a per-device basis. The payment plan ranges between $25 to $50 per device per year, doubling with each passing year. Microsoft will offer this extended support to Windows 7 devices for an additional 3 years, ending it in January 2023. Windows 7 Professional, Windows 7 Enterprise, and Windows 7 Ultimate can avail this extended support plan.

The company has now revealed that businesses can purchase Extended Security Updates (ESU) starting from April 1, 2019.