ASP.NET Core Web API supports RESTful services. It uses controllers to group endpoints, with each endpoint being rendered through an action.
Web API's are used to integrate with applications that share data. They allow you to perform create, read, update and delete methods.
Benefits to using a Web API include the ability for more than one application to share data. You can also have the same instance of a Web API hosted in different locations.
Away from ASP.NET Core applications, you can also integrate a ASP.NET Core application with front-end technologies, such as React, or Blazor Wasm.