What is the purpose of Add Node?
To add a node to regions, polylines, and arcs. You can add nodes when the Reshape command is in effect. Adding nodes can give more precision to your object.
When is Add Node active?
When a single region, polyline, line, or arc is selected from an editable map layer.
How do I access Add Node?
On the SPATIAL tab, in the Edit group, click Nodes, and click Add Node.