You may find some interesting properties to play with from here. Here I explain how you can set border:
h2 {border: 1px dashed red}
The border property has the name border, and you have to set 3 values to it, separated using white spaces. The first one is the width of the border; the second one is the style, selected from solid, dashed, and dotted; and the last one is the color. The following H2 is formatted using the above border code: