How can one address encoding/charset problems when dealing with special characters like ä in PHP?

When dealing with special characters like ä in PHP, it is important to ensure that the encoding/charset is properly set to handle these characters. One way to address encoding/charset problems is to use the UTF-8 encoding, which supports a wide range of special characters including ä. To do this, you can set the charset header in your PHP script to UTF-8 using the header() function.

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