How can I shoot a projectile into mouse position?

Hello. I run into a problem becouse i dont know how to shoot bullet at mouse direction. Thats my code so far:`

void Update()
    {
        if (Input.GetButtonDown("Fire1"))
        {
            float mouseX;
            float mouseY;
            mouseX = Input.mousePosition.x;
            int intMouseX = (int)mouseX;
            mouseY = Input.mousePosition.y;
            int intMouseY = (int)mouseY;

            Vector2 FinalMousePos;
            FinalMousePos.x = intMouseX;
            FinalMousePos.y = intMouseY;

            Instantiate(bullet, Gracz1.transform.position, Gracz1.transform.rotation);
            bullet.GetComponent<Rigidbody2D>().velocity = FinalMousePos * Bulletspeed;
        }

    }

Thanks for help.

Ok i completely revamped my entire script. Now it looks like this:

if (Input.GetButtonDown("Fire1"))
        {
                clickPos = Vector3.one;
                Vector3 punktA = new Vector3(1, 2, 0);
                Vector3 punktB = new Vector3(2, 1, 0);
                Vector3 punktC = new Vector3(3, 3, 0);
                Plane plane = new Plane(punktA, punktB, punktC);
                Ray ray = cam.ScreenPointToRay(Input.mousePosition);
                float DistanceToPlane;
                if (plane.Raycast(ray, out DistanceToPlane))
                {
                    clickPos = ray.GetPoint(DistanceToPlane);
                }
                Vector3 finalClickPos = new Vector3(clickPos.x, clickPos.y, 1);
                Instantiate(bullet, transform.position, Quaternion.LookRotation(finalClickPos));

        }

It works ok but when i instentiate bullet it gets rotated to the opposite corner (for instance when i click in the upper right my bullet gets rotated towards upper left corner) How can i fix this?
@RustyCrow

Try →

var mousePosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
bullet.GetComponent<Rigidbody2D>().velocity = (Character.position - mousePosition).normalized * bulletSpeed

Edit :
Things in Arrow brakets dosent show up. so i added it in as code. Also added how to get mouse world position since OP did not do it correctly.