In CSS margins are used to control space around an HTML element.

Margins create space between other element and browser window

For individual sides(top, bottom,right,left) we can set different sizes of margins

Margins are completely transparent and doesn't have any background color

Margin properties can have the following values:

Length in cm, px, pt, etc.
Width % of the element.
Margin calculated by the browser: auto.

margin properties:

margin-top:Indicates the margin on the top of an element.
margin-right: Indicates the margin on the right side of an element.
margin-bottom:Indicates the margin on the bottom of an element.
margin-left: Indicates the margin on the left side of an element.
Note: The margin property allows negative values.