Hi @Bilal shafi ,
I'm not familiar with CORE PHP but I think all you would need is a .htaccess file that contains rewrite rules.
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{REQUEST_URI} ^(.*)
RewriteRule ^my-old-url.html$ /my-new-url.html [R=301,L]
</IfModule>
If CORE PHP is based of PHP 8, then for App Service, you will need to use rewrite rules for nginx as PHP 8 runtime is no longer based on Apache, see https://azureossd.github.io/2021/09/02/php-8-rewrite-rule/.