include css to html code example

Example 1: how to link css to html

<link rel="stylesheet" href="styles.css">

Example 2: add stylesheet html

<link rel="stylesheet" type="text/css" href="style.css">

Example 3: css without separate file

just add any style inside the first <p> or other element tag using style=" ;" 
<p style="font-size: xx-large;">test</p>