The w3-margin class adds 16px margin to all sides of an element.
The w3-margin-top class adds a 16px top margin to an element.
The w3-margin-bottom class adds a 16px bottom margin to an element.
The w3-margin-left class adds a 16px left margin to an element.
The w3-margin-right class adds a 16px right margin to an element.
The w3-section class adds a 16px top and bottom margin to any HTML element, and can be used to separate sections of HTML content: