Use Insert Points 
to add a point to the currently selected line.
Insert Points is enabled until another tool is selected, or you right-click to deselect.
Shortcut
-
Draw tab, Points:
Add a Point to a Line
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Click the Edit Points icon
to make sure that you are in Edit Points mode.
-
Click the line that you want to edit. The points will be displayed.
-
Click the Insert Points icon
. The pointer changes to the Insert Points pointer 
.
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Click the place on the line where you want to add a point.
Click the line to display the points
Click to add a point
The line will be reshaped accordingly. The Insert Points tool is active until another feature is selected, or you right-click to deselect.