We all know the Feedback and Mobile App buttons are essential for Microsoft, but many of the customers are ask to remove it. The main reason is customer thinks feedback will go to site owner but the actual behavior is the feedback will go to Microsoft.
The following CSS removes the buttons from the page
// Hide any class that starts with feedback
display: none !important;
The CSS query all div elements where that has a class name starting with ‘feedback_’, and this matches the outer container where the buttons are.
Registration through a custom action
The solution built can be deployed tenant wide, so that the button will be removed across the site collections in tenant.
Create an application customizer and add the css to. scss file of your extension. The buttons are removed once the custom action injected to the site.