A catch-all email address is a configuration on a mail server that redirects all emails sent to a domain, regardless of the specific username or email address, to a designated mailbox. In other words, it acts as a "safety net" for all emails sent to a domain, even if the specified email address has not been explicitly created.
This means that if someone uses a random or non-existent email address at that domain, the email will still be delivered to the catch-all address. This feature can be useful in situations where you anticipate emails being sent to various possible addresses within a domain and want to ensure that no messages are lost due to potential typos or variations in the addresses used.
