how do i add speed to my object?

how do i add speed to my object? i have a script but doesn’t include speed

I want to have the option to make object go faster or slower

Can i see your script?

heres 1 of the scripts

#pragma strict

var myCamera : Camera;

function Update () {

var vec : Vector3 = myCamera.ScreenToWorldPoint(Input.mousePosition);
var side : float = 66.0;   // was 8  and 9, this is 4 hand how far on screen want 2 allow to go
var top : float = 66.0;
vec.x = Mathf.Clamp(vec.x, -side, side);
vec.y = Mathf.Clamp(vec.y, -top, top);
vec.z = 0.0;
transform.position = vec;

}