All i'm doing is added a hinge for cframe and I want to know how to remove that yellow cylinder that appears when you add hinge to a surface.
Just make it invisible. Add this local script to the yellow cylinder
script.Parent.Visible = false
You can't... But you could use Constraint to hide it instead of using hinge surface
Just turn off the "Visible" property in the Properties tab. Always works for me and I have tried it with the hinge before.