Cannot find updates when I open system preferences? Can you tell me where this can be found

Software update missing?

Software update may not be available for the macOS installed on your Mac.

Consider upgrading to a later version if compatible with your system.

Update: A later version of the currently installed software. Learn about macOS Big Sur updates, for example.

Upgrade: A major new version, often with new system requirements. Each macOS upgrade has a unique name, such as macOS Big Sur.

 Learn more about installing the latest macOS upgrade. Some old versions of macOS are also available.

Published Date: June 11, 2021

    https://support.apple.com/en-us/HT201541

The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.

With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install. Make sure to use Only Safari to commence the download as Others may not work

Make a Time Machine Backup Before attempting. Notation - Mojave is the Last version to support 32 bit applications / extensions and Drivers. Catalina and Big Sur Only support 64 bit and there is no workaround.

Are there any AntiVirus, Disk Cleaner, Optimizers, Un-installers, etc installed which should be removed as per Developers Instructions. They are useless, unneeded, cause havoc and interfere with the normal operation of the OS and may even Corrupt the OS requiring a Reinstallation