How a local video can be added to a page? How multiple video option can be provided? (This is also valid for audio only.)

It can be added by using the video element:

<h1>Embedded video (webm and mp4 fallback)</h1>
<video src="assets/videos/flower.webm" controls width="600">
    Sorry, your browser doesn't support embedded videos. Download it from <a href="assets/videos/flower.mp4">here</a>.
</video>

We can provide multiple video options by using the source element. We should provide alternative video formats for incompatible browsers:

<h1>Embedded video (webm and mp4 fallback)</h1>
<video controls width="600">
    <source src="assets/videos/flower.webm" type="video/webm">
    <source src="assets/videos/flower.mp4" type="video/mp4">
    Sorry, your browser doesn't support embedded videos. Download it from <a href="assets/videos/flower.mp4">here</a>.
</video>

All of this is also valid for audio only, through the audio element.