Hi there NK199,
Thanks for reaching out to Apple Support Communities. We understand you’d like to archive a backup that’s saved to your computer. We’ll be happy to assist.
This resource has the steps you’d use to archive your backup: Locate backups of your iPhone, iPad, and iPod touch. Specifically, you’ll want to look at the section that says, “Backups on your Mac”
You’ll open the Finder > General tab > click Manage Backups. There you should see a list of available backups. If you right-click on a backup you should get an option to archive it. We hope that helps.
Take Care!