How can the HTTP-Response Header affect the display of special characters in PHP?

The HTTP-Response Header can affect the display of special characters in PHP by specifying the content type and character encoding. To ensure proper display of special characters, it is important to set the content type to "text/html" and the character encoding to "UTF-8" in the HTTP-Response Header. This will ensure that special characters are rendered correctly in the browser.

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