How to Make a Blur all Faces in a Videos in YouTube

YouTube provides a tool automatically hide the identities of the persons appearing in a video.

 
To use this tool:

1- Sign-in to your YouTube Channel

2- Go to My Channel  >>  Video Manager  >>  Videos 

3- Select the video you want to edit  >>  Click on Edit

4- Click on the Enhancements button

5- Click on Special effects tab

6- Next to Blur All Faces , click on Apply

That's it!!