Hello,
3 weeks ago, I applied to become a content moderator but I have not heard from since.
Is this normal? Is there a notification when our application is viewed?
Thanks for your reply.

If it's been 3 weeks and you haven't been contacted, most likely it means the application has been rejected. Other users have reported similar experiences which leads me to believe you don't get notified unless you're accepted.

Yeah you don't get any kind of notification or reply unless they're looking to bring more people on and choose you.