Annotations are the small pop-up boxes that appear in some of the videos you watch on YouTube. If you wish to deactivate these in-video notifications, this tutorial will walk you through the different methods that can be used to hide annotations and notifications.
If you would like to hide an individual annotation from a video, simply place your mouse cursor over the box and click on the small x button.
Disable Annotations for a YouTube Video
To turn off all the annotations for a video, click on the small cog icon (playback menu), and then toggle the Annotations switch Off:
Annotations and cards will be disabled for the entire duration of the video.
Permanently Turn Off YouTube Annotations
If you'd like to permanently disable annotations for all YouTube videos, you can turn off this feature in your account settings.
Sign in to YouTube with your Google account. Next, click on your profile badge and select YouTube Settings (cog icon). Go to Playback > Annotations and in-video notifications and clear the Show annotations and in-video notifications checkbox: