To contact a YouTube channel directly via YouTube, go to the channel page and then click the “about” tab. Scroll down to the “details” section and then click “view email address.” After you should see an email address, which you’d then click and email.
Here is an image of what you should see when you go to the “about” section.
This is the only way to contact a YouTube channel directly from the YouTube channel. Now, you can also indirectly contact the channel by leaving a comment on of their videos. This is especially useful if the reason you want to contact the channel owner is because you have a question or comment regarding on of their particular videos.
You can also go to the same “about” section and click through to the listed website if there is in fact a website listed. From there, try and find the website’s “contact” page and then follow the provided contact opportunities.
Now, if you go to the “about” section and there isn’t an email address or a website, you’ll have to resort to leaving a comment.