I am attempting to install my purchased office home and business 2019 Microsoft to my computer. The software currently has 10.12.6 and it says I need

You don't.

The currently available version of Office requires macOS 10.14 or higher.

Microsoft no longer sells a version of Office that runs on 10.12 or 10.13.

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

Different models of Macs can install and run different operating systems. It depends on your Mac's year and model as to whether you can upgrade it. OS upgrades can be found in the Apple App store. If you are unable to upgrade, and cannot therefore install Microsoft Office, you can install another app which does open Microsoft files and can save as Microsoft files. One good app that does this is LibreOffice. Also, you can do this with the free apps provided by Apple. They are Pages and Notes. You should already have them installed.