YouTube is a popular video-sharing platform where users can upload, share, and view videos. One of the key features of YouTube is the ability for users to leave comments on videos. Comments are a way for users to share their thoughts and opinions about a video, ask questions, or engage in discussions with other users.On YouTube, comments can be found directly under the video that you are watching. To leave a comment, you will need to be logged into your YouTube account. Once you are logged in, you will see a text box where you can type your comment. You can also add emojis, links and images to your comment by clicking on the respective icons on the text box.Users can also reply to comments left by others. To reply to a comment, simply click the 'Reply' button under the comment you want to respond to. This will open a new text box where you can type your response. You can also see other users' replies to a comment by clicking on the 'View Replies' link under the comment.YouTube also allows users to sort comments by relevance, time, and popularity. The default setting is relevance, which displays comments that are considered most relevant to the video and the conversation. Time displays comments in the order they were posted, and Popularity displays comments that have the most likes.Additionally, YouTube allows users to filter comments based on keywords, and also allows users to report comments that violate the platform's community guidelines. Users can also disable comments on their videos if they choose to do so.In summary, YouTube is a video-sharing platform where users can leave comments on videos. Comments are found directly under the video and users need to be logged in to leave a comment. Users can also reply to comments, sort comments by relevance, time, and popularity, filter comments based on keywords, and report or disable comments that violate the platform's community guidelines.