Update computer to macOS Big Sur from macOS Catalina version 10.15.7

Updates are shown automatically, while upgrades have to be requested. Updates are minor fixes and minor enhancements, and are intended to be compatible with existing apps. Upgrades are larger and more complex, and can potentially derail some existing apps.

Here is how to upgrade: How to download macOS - Apple Support

Have a backup from prior to the upgrade, as that’s the only way to back out an upgrade should something go sideways.

is the Mac compatible with Big Sur? you need to have one of these: