How can the correct character encoding be ensured when working with text files, databases, and HTML output in PHP?

When working with text files, databases, and HTML output in PHP, it is important to ensure that the correct character encoding is used to avoid issues like garbled text or special characters displaying incorrectly. To ensure the correct character encoding, you can set the charset in PHP using functions like mb_internal_encoding() and mb_http_output(). Additionally, when working with databases, make sure that the database connection is set to use the correct character encoding.

// Set internal encoding to UTF-8
mb_internal_encoding('UTF-8');

// Set HTTP output encoding to UTF-8
mb_http_output('UTF-8');

// Set database connection to use UTF-8
$mysqli = new mysqli('localhost', 'username', 'password', 'database');
$mysqli->set_charset('utf8');