How to Embed a YouTube or Vimeo Video into Your Post
Embedding a YouTube or Vimeo Video into your post is one of the simplest things you can do on WordPress. The way WordPress is configured, you just have to be sure to use a hard return (vs. a soft return) and enter the entire URL (including the http://) of the video from the browser URL area of YouTube or Vimeo and it will automatically embed the video for you.
If you do not copy and paste the URL on its own line, it will appear just as copied and it will not embed. The trick is to remember it has to be on its own line where you want it to embed in your post. It will play within your post on wordpress.