How can setting the content type and charset impact the display of special characters in PHP?

Setting the content type and charset in PHP is crucial for displaying special characters correctly. If the content type is not specified or set to a default value, special characters may not render properly on the webpage. By specifying the content type as "text/html" and setting the charset to UTF-8, you ensure that special characters are displayed correctly.

header('Content-Type: text/html; charset=utf-8');