You cannot directly tag a person in a YouTube video title or description the way you can on some social platforms
To mention someone in a comment, type `@username`
To mention someone in a community post, type `@username`
To mention someone in a video description, type `@username`
Make sure the person has a YouTube handle
Select the correct account from the autocomplete suggestions
Use the exact handle if available
If you want to credit someone in a video, add their channel link in the description
If you want to notify someone, mention them in a comment or community post