You can easily download videos from video sharing site YouTube easily without installing any downloading software. The only thing you have to do is just editing the URL as follows.
1. Open the video you want to download in any browser
2. insert ‘ss’ replacing ‘https://www.’
eg: https://www.youtube.com/watch?v=jKb.R7u8J5PU
new URL : ssyoutube.com/watch?v=jKb.R7u8J5PU
press ENTER
3. This will redirect you to saveform.net
4. Select the video quality needed and your file will be downloaded.