Override Standard Actions with Lightning Components

Add the lightning:actionOverride interface to a Lightning component to enable the component to be used to override a standard action on an object. You can override the View, New, Edit, and Tab standard actions on most standard and all custom components. Overriding standard actions allows you to customize your org using Lightning components, including completely customizing the way you view, create, and edit records.

Overriding an action with a Lightning component closely parallels overriding an action with a Visualforce page. Choose a Lightning component instead of a Visualforce page in the Override Properties for an action.Override a standard action with a Lightning component

However, there are important differences from Visualforce in how you create Lightning components that can be used as action overrides, and significant differences in how Salesforce uses them. You’ll want to read the details thoroughly before you get started, and test carefully in your sandbox or Developer Edition org before deploying to production.