Posting videos (especially YouTube) on WordPress

It seems that I can no longer post a video – more specifically a YouTube video to WordPress. It asks for the video URL as opposed to the embed code. Three attempts, three different wrong results. I get:

watch?v=mOgFoitNru0

https://www.youtube.com/watch?v=mOgFoitNru0

<script src=”https://i.cdn.turner.com/cnn/.element/js/2.0/video/evp/module.js?loc=dom&vid=/video/international/2009/06/07/damon.indo.food.security.cnn” type=”text/javascript”></script><noscript>Embedded video from CNN Video</noscript>

All three were put in fields after I clicked onto the “Add a video” button. What am I doing wrong? Thanks!!