That means that any bugs or problems still found in Windows 7 will never get fixed. Likewise, any security vulnerabilities could also remain in Windows 7, as Microsoft is unlikely to patch those unless they are very severe.
Computers running the Windows 7 operating system will continue to work even after support ends. However, using unsupported software may increase the risks from viruses and other security threats.
To avoid any security risks post the end of support, users and organizations are advised to upgrade to the latest software or an alternative operating system.
CERT-In Advisory CIAD-2019-0012 End of Life for Windows 7