Explanation
Client-side scripting using JavaScript is one of the ways to apply custom business process logic for displaying data on a form in a model-driven app.
You can use a community tool, Ribbon Workbench, to visually edit ribbons using the UI.
Reference:
https://docs.microsoft.com/en-us/powerapps/developer/model-driven-apps/client-scripting
https://docs.microsoft.com/en-us/powerapps/developer/model-driven-apps/customize-commands-ribbon