What are common issues related to character encoding when working with PHP scripts?

Common issues related to character encoding when working with PHP scripts include displaying special characters incorrectly, handling multibyte characters improperly, and encountering encoding mismatches between different components of the application. To solve these issues, it is important to ensure that the character encoding is consistent across all components of the application, use functions like mb_convert_encoding() to handle multibyte characters properly, and set the appropriate charset in the HTML document.

// Set the character encoding to UTF-8
header('Content-Type: text/html; charset=UTF-8');

// Convert a string to UTF-8 encoding
$utf8_string = mb_convert_encoding($original_string, 'UTF-8', 'auto');