There are two ways to access the Right mouse button menu customization page.
Right mouse click in the ribbon area > Customize Quick Access Toolbar/Customize the Ribbon
Select Context Menu.
FILE > Options
Select Context Menu. All items currently setup for the Right mouse button menu are listed.
To add additional tools, select the appropriate Category from the drop down menu. Select the desired feature and select the Add button.
To remove a tool, select the tool that will be removed and select the Remove button.