I will share eventually my first project on a private site I’ve done on Wordpress.
The html code have no preview on wordpress, because:
Does This Work With Any URL?
No, not by default. WordPress will only embed URLs matching an internal whitelist. This is for security purposes.
So, wich I need to use from those 2 option:
How Can I Add or Change Support For Websites?
Adding support for an additional website depends on whether the site supports oEmbed.
Adding Support For An oEmbed-Enabled Site
If a site supports oEmbed, you’ll want to call wp_oembed_add_provider() to add the site and URL format to the internal whitelist.
Adding Support For A Non-oEmbed Site
You’ll need to register a handler using wp_embed_register_handler() and provide a callback function that generates the HTML.