Videos are easily included in websites today thanks to YouTube.

I use the JCE replacement Editor which has the ability to embed videos from web URLs and directly. There are also many add-ons and plugins available for site software, the Allvideos plugin for Joomla works well too. All that's needed is the URL of the YouTube clip like this: https://www.youtube.com/watch?v=NKON45gIkmA

Using the JCE Editor, you can select the INSERT/EDIT MEDIA button, select the type of video you want to dispplay, enter the on-line video source URL and click Insert.

It's as easy as that.

You can also add videos by uploading files to the server and linking to them in a similar manner.

This is just a small example of one of the many plugins available for the Joomla CMS. Many templates have built in image and video display options so if you're site is designed primarily to display them, then choosing a template may be an easier way to manage the files.