Enable YouTube Video Plugin
There are lots of plugins available to enable the YouTube Video download option in Firefox browser.
Below I have mentioned the installation procedure of 1-click YouTube Video Download
1. Go to the following link in Firefox browser.
2. Click on the Add to Firefox button
3. This will download the add-on and open the installation window
4. Click on the Install Now button. After the installation reboot the browser.
5. Now you can see the download option in the YouTube video
6. Click on the required format and save it to your local disk.