wrap naother page or code

Hi,

I want to include another page in my wordpress.
I was using joomla before and this was easy with a wrapper to include some
code that I ‘ve written or to include another site.

I don’t know if it’s possible with wordpress. I haven’t found something till
now.

I will be grateful if someone send me a link or a plugin name that does this work.

Thanks,
Dinos