When you draw shapes, Smart Guides (‘View’ – ‘Smart Guides’) help by showing the shape and size in a grey measurement label, snapping to other objects, and indicating when an ellipse is a perfect circle or when a rectangle is a perfect square with magenta lines.
Most shapes are Live, which means you can edit them without switching tools after drawing. Different shapes have widgets for editing corner radius, number of sides and more.
To show other shape tools, click and hold the ‘Rectangle Tool (M)’ in the Tools Panel
When you click on a shape with the ‘Selection Tool (V)’ a ‘Bounding Box’ appears. This allows you to edit shapes.
Press and hold the ‘Rectangle Tool’ to choose from different shapes. If you would like a polygon that is not shown in the menu select the ‘Polygon Tool’
The ‘Polygon Tool’ draws shapes from the center
Press and hold the shift key to straighten
Another way you can make simple shapes is by the ‘Shaper Tool (Shift + N)’. If you click and hold the ‘Shape Boolean Tool’ you can access the ‘Shaper Tool’. This tool allows you to click and draw a basic shape. Once you let go of the mouse Illustrator will interpret your drawing turn it into a perfect polygon.
With the ‘Selection Tool’ active you can move a shape by clicking and dragging the circle/square in the center of the shape.
Click and drag the solid boxes in the corner to resize
Click and drag the widget in the corners of the box toward the center to round the corners
Hover your mouse near the corner of the square (with the ‘Selection Tool’ still active) once the mouse turns into a curved line with arrows on either end you can rotate the selected shape
The ‘Polygon Tool’ has similar widget features to the square. (IE: Moving, Rotating, Rounding Corners, and Resizing)
Press and drag the diamond up and down the right side of the bounding box to change the number of sides the polygon has.