You configure a “private” email account for one or many users who will be receiving and sending email from your domain. Once an email address is configured as a pop mail account, it operates privately and independently from your main standard/default mail system. Any mail sent to a private pop mail account “can only be received” by logging into that account with the separate username and password you have assigned it.

POP3 accounts are useful if there are a number of people who would each need a private email account.