Our Mac is on 10.11.6 and need to update but it will not. Any suggestion

You can upgrade to macOS High Sierra. Get it here: How to get old versions of macOS - Apple Support. Backup before upgrading!

Cheers,

Jack

Hi JV76,

Please go to the Apple Menu (top left) > About This Mac, and let us know what year of Mac you have.

Cheers,

Jack