To embed a YouTube video in an HTML page, you can use the <iframe> element. The src the attribute should contain the URL of the YouTube video, and the width and height attributes should specify the dimensions of the video player.

For example:

<iframe src="https://www.youtube.com/embed/dQw4w9WgXcQ" width="560" height="315" frameborder="0" allowfullscreen></iframe>

This will embed the YouTube video with the URL https://www.youtube.com/watch?v=dQw4w9WgXcQ in the HTML page, with a width of 560 pixels and a height of 315 pixels. The frameborder attribute controls the border around the video player, and the allowfullscreen attribute allows the video to be played in full-screen mode.

You can also customize the video player using the ? the parameter in the URL. For example, to hide the player controls and related videos when the video is finished, you can use the following URL:

https://www.youtube.com/embed/dQw4w9WgXcQ?controls=0&rel=0

You can find more information about customizing the YouTube video player in the YouTube API documentation.