Go to the Youtube page containing the video and click and copy as follows in purple mark up.
1) Click on Share - 3 new tabs appear: "Share Embed Email"
2) Click on Embed - appearing is a field with automatically highlighted text (the needed iframe html code for embed).
3) Menu bar item "Edit -> Copy" to capture into local copy/paste buffer, for pasting into the web page body.
Scroll down to continue to 2nd image and it's instructions.