How to know my mail has youtube channel

I think there may be a bit of confusion here!

A "mail" is a physical letter or package sent through the postal service, whereas a "YouTube channel" is an online video sharing platform.

If you're asking how to know if someone has a YouTube channel, here are a few ways:

1. Search for their name: Try searching for the person's name on YouTube to see if they have a channel.
2. Check their social media profiles: Many YouTubers link to their channel on their social media profiles, such as Twitter, Facebook, or Instagram.
3. Ask them directly: If you know the person, you can simply ask them if they have a YouTube channel.
4. Look for their videos online: If you're familiar with their work or content, you can try searching for their videos on YouTube or other video sharing platforms.

If you're asking how to know if a physical mail has a YouTube channel, I'm not sure what you mean by that. Could you please provide more context or clarify your question?