You can draw a rectangle in the following way:

1. Click the Shape Tools from the left toolbar then select the Rectangle tool.

2. Draw a rectangle or a square. You can change the stroke thickness, stroke style and stroke color of your rectangle.

https://cdn.elev.io/file/uploads/Nx6j1ilgYkjKwwUzxKv9Jx2yWyIGUZG4VbEE9W71H30/_-IrqB0T8e65OTT3Bjh-6DROgfAJJsN2_fXHTFOWBnc/drowing a rectangle-hYQ.gif

Stroke thikness:

For changing the stroke thickness, click the Thickness https://cdn.elev.io/file/uploads/Nx6j1ilgYkjKwwUzxKv9Jx2yWyIGUZG4VbEE9W71H30/43rV_bc0O87pHki4Ypjk_mnTSW7o5dlm4-ys0Tz_cec/stroke-size-u74.png field from the Properties toolbar and choose the one you need.

Stroke style:

If you wish to change the stroke style of your rectangle, select it, click the Stroke Style https://cdn.elev.io/file/uploads/Nx6j1ilgYkjKwwUzxKv9Jx2yWyIGUZG4VbEE9W71H30/twmMrfOpBl64qXrW6i4q_4IKi4cK3Us1XPKbL5Wo7DQ/stroke-style-6Fc.png field from the Properties toolbar and choose a style for it.

3. When you’re done save your page or continue editing.

Get more info about changing the fill color of your shape.

Learn more about changing the stroke color of your shape.