The Crop & Bleed Marks Panel
This panel gives the ability to decide if you what Crop marks apply to the selected object, how long the marks should be and even the distance to the object and the stroke weight can be decided. Even a guide can be added. The same guide for the Bleed marks and the Safe marks. The Bleed marks is marks that will go outside the selected object, to let you have extra material on you production. The Safe marks indicate where element should be position of the products where it is safe to be within the selected object.
In this panel you also decide if the marks should be positive or negative - should the marks be black (Registration Color) or white (Paper Color), depending on your design. This setting will also have affect on the registration marks.