script to move an object by a few pixels

I would like to create a script to move an object by a few pixels during the game

This should serve you well:

public class NewBehaviourScript : MonoBehaviour
{
    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Alpha1))
        {
            Vector3 screenCoordinate = Camera.main.WorldToScreenPoint(gameObject.transform.position);
            screenCoordinate += new Vector3(1, 0, 0);
            gameObject.transform.position = Camera.main.ScreenToWorldPoint(screenCoordinate);
        }
    }
}