Custom UI Editor

Adding a customised Ribbon to your Office files means inserting an XML component into the Open Office XML file format.
The steps to add this XML component is documented here.
The Custom UI Editor was a tool created by Microsoft for Office 2007 that would simplify adding the necessary XML component.
This editor could be used for all Ribbon Customisations stored in the Office Open XML Format.
This includes individual workbooks and documents as well as add-ins and templates.
The Custom UI Editor is now officially unsupported by Microsoft. more details

Replacement - Office RibbonX Editor

This is based on the original Custom UI Editor but with some additional features.
This is a GitHub open source project created by Fernando Andreu.
We suggest downloading and using the Office RibbonX Editor with Windows 11.

Creating an Excel Workbook with a Custom Ribbon

More details can be found here Document Level > Editor

Creating an Excel Add-in with a Custom Ribbon

More details can be found here Application Level > Editor