Is it the conventional practice to use API like this

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C#

hi, i have read a article using "interface as callback".
https://www.c-sharpcorner.com/UploadFile/1c8574/delegate-used-for-callback-operation/

then I see that many occasion, Api provides the interface for consumer. I wonder if they are usually working like this way? I think there are 4 steps
here is my code (please correct my comment if i misunderstand, thanks!)

first there is a Api

class Api
    {
        //Api request passing interface object into method      
        public void StartNewTask(IFurtherProcess Interface_Obj_Feedback_from_user)    
        {
            Console.WriteLine("started task");

          //I am Api , I only tell you I started a task , below further process is up to consumer.

            Interface_Obj_Feedback_from_user.process(); // process is sometime Adding, sometime Subtract 
           
        }

    }
    interface IFurtherProcess
    {   
        void process();       //step 1 : Api declare a Interface with method
    }

then there is Class to implement the interface by Consumer

public class ProcessClass1 : IFurtherProcess      //step 2: Api Consumer design class to implement the interface;
    {
        
        public void process()
        {
            Console.WriteLine("add");
            
        }
    }
    public class ProcessClass2 : IFurtherProcess      //step 2: Api Consumer design alternative class implement the interface;
    {

        public void process()
        {
            Console.WriteLine("sub");
            
        }
    }

then there is a ApiConsumer Class:

class ApiConsumer    //created by consumer
   {
       public IFurtherProcess _ifp=null;
           public ApiConsumer(IFurtherProcess ifp)   //leave it for main to choose what ifp is ?
       {
           this._ifp = ifp;

       }
      public void CallApiMethod()
       {
           Api cs = new Api();
           cs.StartNewTask(_ifp);
       }

   }

finally, it is the main:

static void Main(string[] args)
      {
          ApiConsumer apiConsumer = new ApiConsumer(new ProcessClass2());  // Step 4:i choose Process2 here!
          apiConsumer.CallApiMethod();
          Console.ReadLine();
      }

What I have tried:

furthermore, it seems to have too many layer. Is it so called "wrapper" what i am doing above? main->apiconsumer->api .