Polylines are continuous lines composed of multiple segments. To create them, click the Polyline button from your drawings toolbar, to the left of the Text box button.
After drawing a segment of your polyline, click to end the segment and begin your next segment. When you've finished, connect the endpoint of your last line segment with the origin point of your polyline to create an enclosed shape. Alternatively, click near the endpoint of your last line segment to complete the shape.
If you'd like to rearrange the vertices, double-click the polyline.
If after you started creating a polyline, you change your mind about inserting this shape, simply press the Esc key.