As a YouTube Channel Creator, you can pin or stick a Comments to the highest point of your YouTube video’s “Comments” segment. This will assist your watchers with seeing the best comments when seeing your video. You can pin your own comments or another user’s comment. See detail in following Picture.
Visit Youtube.com or open your existing video
Navigate to the “Comments” section and select the comment which you want to pin. Open your videos and scroll down to the “Comments” section.
Click on the Pin option from the drop down menu.
Finally you have Pin your comment?