To Place a Polygonal (Non-Rectangular) Fence

Select the Place Fence tool ( Drawing > Home > Selection > Fence Tools split button).

If a fence already exists, it is removed.
In the tool settings window, set Fence Type to Shape.
Enter a data point to define the beginning (and end) point.
Continue to enter data points to define the vertices.
Do one of the following:

To close the shape, enter a data point at the location of the first data point.

or
Click the Close button.

or
Type CLOSE ELEMENT.