💬 In plain words: Buttons and actions are how users get things done on a record. Quick Actions are the native way to do this in Salesforce Lightning. JavaScript buttons are completely dead. Page Layouts still control basic field and related list availability, but the Lightning Record Page handles the overall component structure. Finally, Dynamic Forms takes things to the next level by letting you put individual fields right on the page and hide them based on specific rules. 📌 Real-Life Example: Imagine an older Salesforce org with a custom JavaScript button that recalculates an order total. If you switch to Lightning, clicking it does absolutely nothing. The modern fix? Rebuild it as a Quick Action that launches an auto-launched Flow, a Screen Flow, or a Lightning Web Component ( LWC ) that calls Apex. The user still clicks a button, but underneath, it uses a supported, modern mechanism.
Lightning Web Components