There are three ways of inserting a style sheet: External CSS; Internal CSS; Inline CSS. External CSS.

1. With an external style sheet, you can change the look of an entire website by changing just one file!

   Each HTML page must include a reference to the external style sheet file inside the <link> element, inside the head section.

2. An external style sheet can be written in any text editor , and must be saved with a .css extension.

3. An internal style sheet may be used if one single HTML page has a unique style.

   The internal style is defined inside the <style> element, inside the head section.