how to add a speed limit?

[Ardito]

foreach (Touch input in Input.touches)
{
if (input.phase == TouchPhase.Moved)
{
Vector3 screenPoint = new Vector3 (Input.mousePosition.x, 65);
screenPoint.z = 11; //distance of the plane from the camera
transform.position = Camera.main.ScreenToWorldPoint(screenPoint);
}
}

The object follows the touch, but how do I get it moving with a velocity from position A to position B?

[dmg0600]

You could do it using Lerp.

public float speed = 5f;

private Vector3 origin;
private Vector3 destination;
private float timeToTravel = 0f;
private float currentTime = 0f;
private bool isMoving = false;

WhateverMethod()
{
    ...

    foreach (Touch input in Input.touches)
    {
        if (input.phase == TouchPhase.Moved)
        {
            origin = transform.position;

            Vector3 screenPoint = new Vector3 (Input.mousePosition.x, 65);
            screenPoint.z = 11; //distance of the plane from the camera
            destination = Camera.main.ScreenToWorldPoint(screenPoint);

            timeToTravel = (origin - destination).magnitude / speed;
            isMoving = true;
        }
    }

    ...
}

void Update()
{
    if (isMoving)
    {
        currentTime += Time.deltaTime;
        
        if (currentTime <= timeToTravel)
        {
            transform.position = Vector3.Lerp(origin, destination, currentTime / timeToTravel);
        }
        else
        {
            transform.position = destination;
            currentTime = 0f;
            isMoving = false;
        }
    }
}

There are cleaner ways to do it, but this will work.