Of course, in most circumstances, it is best to upgrade. Windows 7 is dated and missing the security features of Windows 10.

For businesses, Microsoft offers extended support via critical security patches for Windows 7. You need to contact them to find out pricing, but you’ll likely find out the pricing is $50 per Windows 7 instance for an added year. The next year will be $100 and a third for $150 each. More information: https://support.microsoft.com/en-us/help/4497181/lifecycle-faq-extended-security-updates

Home users are not supported. However, many people find that Microsoft allows them to use their Windows 7 license key to activate Windows 10. The path isn’t super easy, but possible. Here is more information: https://www.howtogeek.com/266072/you-can-still-get-windows-10-for-free-with-a-windows-7-8-or-8.1-key/