Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Dear respected Rosa,
As per the detailed description, I understand that your MacOS is 11.7.10 which is no longer available to update. Please don't worry, you can still install and work with Office apps on your Mac with a previous version.
According to the official recommendation, the September 2023 update (16.77) is the last build to support macOS Big Sur 11.7. If you want Office version package on your Mac OS 11.7.10, you can download the Version 16.77 from this link Office suite (with Teams).
You can also download the installer package or specific Office apps from this official page to customize:
Update history for Office for Mac - Office release notes | Microsoft Learn
Appreciate your understanding that sometimes the initial reply may not resolve the situation very soon. However, we can work together to narrow down and resolve the situation. Please kindly post back and provide the more information, then we can focus on your specific scenario and provide specific suggestions.We'll be here for you to wait for your updates. I appreciate your time and effort on checking these above and thank you for your patience and cooperation. I hope that you are keeping safe and well!Sincerely,Mia | Microsoft Community Moderator