Insert edges to add more control in specific areas.
On the ribbon, click 3d Model tab Freeform panelInsert Edge . If necessary, click the drop-down menu to access Insert Edge.
Select Edges.
Specify the location value - the location value controls the position of the new edge using a decimal percentage. That is, this value determines how to divide the area between the 2 selected edges. The amount entered must be between -1 to 1.
Mode
Specify Simple to insert the edge without moving the other edges. The shape of the body may change.
Specify Exact to maintain the current shape. Additional edges are automatically added.
Specify the insertion side: Single or Both. The Both option adds an edge on each side of the selected edge.
Select OK
Note:
Hold the CTRL key to add edges. Hold the SHIFT key to remove edges.