How can the header function be used to set the character encoding in PHP applications?

To set the character encoding in PHP applications, the `header` function can be used to send an HTTP header with the appropriate charset parameter. This ensures that the browser interprets the text in the correct character encoding, such as UTF-8, which is commonly used for web content. By setting the character encoding in this way, it helps prevent issues with displaying special characters or symbols on the webpage.

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