How can PHP developers handle Umlauts and special characters in URLs effectively?

PHP developers can handle Umlauts and special characters in URLs effectively by using the `urlencode()` function to encode the special characters before including them in the URL. This function will convert the characters into a format that is safe for use in URLs. When receiving a URL with encoded special characters, developers can use the `urldecode()` function to decode them back to their original form.

// Encode special characters before including them in the URL
$special_characters = 'äöü';
$encoded_characters = urlencode($special_characters);

// Decode special characters when receiving a URL with encoded characters
$decoded_characters = urldecode($encoded_characters);

echo $encoded_characters; // Output: %C3%A4%C3%B6%C3%BC
echo $decoded_characters; // Output: äöü