To add an anchor on an existing curve
 on the curve and select Curve Point from the marking menu.
 on the curve and select Curve Point from the marking menu. 
            Maya inserts an anchor into the curve with a pair of tangents.
To append anchors to the end of an existing curve
 ) in the Curves shelf.
) in the Curves shelf. 
            The last anchor is always the end point of the curve that is not yellow.
 on the curve and select Control Vertex from the marking menu.
 on the curve and select Control Vertex from the marking menu. 
             .
. 
                
               You cannot remove tangents the same way as removing an anchor. For more information, see Add / Remove tangents.