How can PHP headers affect frame redirection and URL display in the address bar?

When using PHP headers to redirect frames or URLs, it is important to ensure that the headers are set before any content is output to the browser. If headers are sent after content, it can cause errors or unexpected behavior, such as the URL not displaying correctly in the address bar. To fix this issue, make sure to set the headers at the beginning of the PHP script before any HTML or text output. This will ensure that the headers are sent to the browser before any content, preventing any conflicts or display issues.

<?php
header("Location: https://www.example.com");
exit;
?>