How to allow loading a page in iframe on Messenger and Facebook domains

Question

I am using iframe to display a page on facebook Messenger web following the below article :

https://developers.facebook.com/docs/messenger-platform/webview/extensions#webview_on_web

I already whitelisted my domain but now I want to allow the loading of these pages on iframe. For that I need to set X-Frame-Options HTTP response header to allow my page within an iframe.

X-Frame-Options: ALLOW-FROM https://www.messenger.com/

My question is how and where to set this response header.

Vange

Depends on your system ... Could happen at the web server level, could happen from within your server-side script code, ... – Extrasensory

Your .htaccess file is probably the easiest place. – Bud

@CBroe in case you're using php how would you set that in the script files? – Mckelvey