Is there any way to securely use Microsoft Windows 7 after the end of support?
The support for Windows 7 ended January 14, 2020. Microsoft offers its customers to purchase three additional years of support via Windows 7 Extended Security Updates (ESU). ESU is available for Windows 7 Professional as well as Windows 7 Enterprise and must be purchased for single years (2020, 2021, 2022). When purchasing Windows 7 ESU in the second year (2021), payment for the first year (2020) is due as well. ESU does not renew automatically, but must be purchased separately for each single year. Software Assurance is not required to use ESU.
Source: official Microsoft Windows 7 Extended Security Updates FAQ website (https://support.microsoft.com/en-in/help/4527878/faq-about-extended-security-updates-for-windows-7), retrieved 2020-02-14