Salesforce has separate sections for custom buttons that show in Classic and Lightning. Initially, both use the same list of custom buttons, but they are separate when an administrator overrides the “Salesforce Mobile and Lightning Experience Actions” setup in the page layout.
Page Layouts in Lightning
- Drag the Super Clone Pro custom button from the collection of buttons onto the “Mobile & Lightning Actions” section of the page.
- If the “Salesforce Mobile and Lightning Experience Actions” are not overridden, see adding a custom button for classic below.