Official support for Windows 7 is ending on January 14th. Before then, you can either upgrade your existing computer to Windows 10 or buy a new computer with Windows 10 already installed. Or buy a Mac, ChromeBook, or give up your computer technology ways and get a yellow legal pad with one of those 4 color pens that my dad was so fond of.
Should you want to upgrade your existing computer, a couple of things.
First of all, Windows 10 is FREE. You can download it from a variety from Microsoft (do a search for Media Creation Tool 1903 and have a > 8 GB USB stick that can be erased available for this). You can do this upgrade yourself but it's not simple. Hire a pro if you're not sure.
My recommendation is unless you have a really good computer, it's time to go buy a new one. I have upgraded it a half dozen times this week on a variety of computer makes and models. On average, you're looking about 2 1/2 hours of you or me staring at it, drinking your coffee, eating your baked goods, and playing with your dogs (and cats, but usually they're wary of computer guys). I did have one upgrade fail on a computer that I own. My business partners have also had upgrades fail, it's not uncommon.
When Windows 7 support ends, your computer will still work, nothing will get deleted, life will not end, birds will not fall from the sky, glaciers will not melt any quicker, but you won't be protected against security flaws and software bugs. Third party software vendors like Intuit, HP, Quicken and Apple may also start requiring you to run Windows 10. An example will be that you'll buy a new printer that may or may not support Windows 7 (just like it's hard to find a new printer that supports Windows XP).