One year from today -- on January 14, 2020 -- Microsoft's support for Windows 7 will cease. That means no more updates or fixes, including security fixes after that date, which is the first Patch Tuesday of 2020, unless a customer pays.
Microsoft officials have announced two ways that Windows 7 users can continue to get security updates beyond the January 14, 2020 date. Both of these ways are designed for business customers, not consumers.
Microsoft will sell paid Windows 7 Extended Security Updates (ESUs) on a per-device basis, with the price increasing each year. These ESUs will be available to any Windows 7 Professional and Windows 7 Enterprise users with volume-licensing agreements, and those with Windows Software Assurance and/or Windows 10 Enterprise or Education subscriptions will get a discount. These ESUs will provide Windows 7 Extended Security Updates through January 2023.
Microsoft also will provide ESUs for no additional cost to customers who buy the Microsoft Windows Virtual Desktop service, which is designed to to allow users to virtualize Windows 7 and 10, Office 365 ProPlus apps and other third-party applications by running them remotely in Azure virtual machines. Those wanting to virtualize Windows 7 after Microsoft support ends in January 2020 will be able to do so for three years by using WVD. WVD still is not available in public preview, but is expected to be sometime this calendar quarter. Microsoft has not yet announced a final availability date or pricing for WVD.
End of "mainstream" support for Windows 7 with Service Pack 1 installed occurred on January 13, 2015. Mainstream support includes no-charge incident support and paid incident support; security update support; and the ability to request non-security updates. End of extended support for the product, on January 14, 2020, means the end of paid support; free security update support; and Extended Hotfix Support.
Windows 8.1 customers will continue to get security updates from Microsoft for free until January 10, 2023. Windows 10 users get free support based on the date when their version of Windows 10 was introduced. (See this Windows lifecycle support page from Microsoft for details.)
Update: If you're wondering what Microsoft's guidance is, re: the pending end of support for Windows 7, it's not simply "move to Windows 10." Microsoft is using the end of support to try to get users to go all the way and move to Microsoft 365, its bundle of Windows 10, Office 365 and EMS. Here's Microsoft's latest migration page, featuring a checklist and reference to a free evaluation lab kit for testing Windows 10 Enterprise, System Center Config Manager, the Windows Assessment and Deployment Kit, App-V, Windows Server and more.