To implement your APEX application into another website (for example an intranet) then you need to use the following iframe script in the html body section:
iframe src="YOUR_SERVER/pls/otn/f?p=APP_ID:PAGE_ID:SESSION_ID:::::" width="400" frameborder="0" height="150" frameborder="0"
iframe src="YOUR_SERVER/pls/otn/f?p=APP_ID:PAGE_ID:SESSION_ID:::::" width="400" frameborder="0" height="150" frameborder="0"
