A catch-all, also called a wild-card email address, refers to your chosen G Suite mailbox for catching all emails sent to any nonexistent email address on your domain, and it doesn’t matter if that nonexistent address is email@example.com or firstname.lastname@example.org. It doesn’t matter the combination the sender uses. So far as the email address is associated with your domain, you will receive the email in your catch-all mailbox.
So by default, you can create a catchall account for the primary domain but the same option is not given for secondary/additional domains. Luckily there is an easy workaround for this and we can create a catchall address for any of your G Suite domains. This quick guide will show you how you can create a catch-all email for any or all of your secondary/non-primary G Suite domains. Read more