How can PHP variables be accessed within an HTML file?

To access PHP variables within an HTML file, you can use PHP tags to echo the variable value directly into the HTML code. This allows you to dynamically insert PHP variables into your HTML content. Simply enclose the PHP variable within `<?php echo $variable; ?>` tags wherever you want to display its value in the HTML file.

&lt;!DOCTYPE html&gt;
&lt;html&gt;
&lt;head&gt;
    &lt;title&gt;PHP Variables in HTML&lt;/title&gt;
&lt;/head&gt;
&lt;body&gt;
    &lt;h1&gt;Welcome &lt;?php echo $username; ?&gt;!&lt;/h1&gt;
    &lt;p&gt;Your email is: &lt;?php echo $email; ?&gt;&lt;/p&gt;
&lt;/body&gt;
&lt;/html&gt;