
Explanation:

Box 1: Add &ribbondebug=true to the end of the application URL.
Scenario: The captions for the New and Save buttons do not render properly on the form.
You can use the an in-app tool called the Command Checker to inspect the ribbon component definitions to help us determine why the button is not rendered correctly.
To enable the Command Checker, you must append a parameter &ribbondebug=true to your D365 application URL. For example:
https://yourorgname.crm.dynamics.com/main.aspx?appid=9ab590fc-d25e-ea11-a81d-000d3ac2b3e6&ribbondeb Box 2: Use the Ribbon Workbench Adding Buttons to Ribbons
* Download and install Ribbon Workbench.
* Select a suitable ICON for your button.
* Create a solution.
* Edit the button in Ribbon Workbench.
* Publish and test.
Reference:
https://support.microsoft.com/en-us/help/4552163/ribbon-troubleshooting-guide
https://neilparkhurst.com/2015/10/19/adding-buttons-to-ribbons/