HOW TO MOVE A OBJECT TO ANOTHER OBJECT SMOOTHLY NOT INSTANTLY?

HI GUYS! ok I want to know how to move an object to another object smoothly, as if im throwing it the other object.

Say I have Object A and Object B.

I want, if I click Object B, then Object A will smoothly go to Object B.

I did this:

using UnityEngine; using System.Collections;

   public class GreenEnvelope : MonoBehaviour
  {
 void Update()
 {
     GreenMail();
 }

 private void GreenMail()
 {
     //the speed, in units per second, we want to move towards the target
     float speed = 40;
     float rotateSpeed = 100f;

     //move towards the center of the world (or where ever you like)
     Vector3 targetPosition = new Vector3(-23.77f, -9.719998f, 0);

     Vector3 currentPosition = this.transform.position;
     //first, check to see if we're close enough to the target
     
         if (Vector3.Distance(currentPosition, targetPosition) > .1f)
         {
             Vector3 directionOfTravel = targetPosition - currentPosition;
             //now normalize the direction, since we only want the direction information
             directionOfTravel.Normalize();
             //scale the movement on each axis by the directionOfTravel vector components

             this.transform.Translate(
                 (directionOfTravel.x * speed * Time.deltaTime),
                 (directionOfTravel.y * speed * Time.deltaTime),
                 (directionOfTravel.z * speed * Time.deltaTime),
                 Space.World);
             transform.Rotate(Vector3.up, rotateSpeed * Time.deltaTime);
         }
  }
  }

but I have to keep clicking the object in order for it to move... I have to keep clicking it everyFrame... thats not what I want. I want to click my "Object B" just once, and my "Object A" will just smoothly go to "Object B"

Please Help! :(