Whenever you watch a video on YouTube, that video is added to your YouTube history by default.
While there feature can sometimes be great for finding that cool video you were watching earlier (you can see a list of everything you’ve watched by clicking ‘History’ on YouTube’s homepage), it can be problematic if you watch a video on the service you’d prefer to never see again.
Your YouTube watch history is a private thing between you and Google, others won’t be able to see your history when going to your profile page. That said, Google does use that info to make recommendations for you. That means you still might want to delete items, especially if watching that one Spice Girls video or the like is skewing your recommendations a direction you’d rather it not.
To clear your YouTube Watch history, tap the hamburger menu (the three lines on top of each other) on the top left side of the page and then select History from the drop-down menu.
When a new menu appears, select “Watch History” and then click “Clear All Watch History.”
You can do the same thing on mobile by taping your Profile rather than the hamburger menu, selecting History, and then selecting “Watch History” from the menu.