You can set up additional e-mail addresses – so-called alias addresses – on the settings page of the mailbox.org web interface. In the settings, select mailbox.org, and then E-Mail Aliases to enter your additional addresses.

Depending on the package, it is possible to specify up to 25 e-mail aliases per account.
All e-mails addressed to these additional addresses are delivered to your inbox. With a single mailbox.org account, it is so also possible to use aliases to specify different sender addresses. Any replies or new e-mails directed to these addresses are then going to get delivered to the same inbox.

Questions and Answers

Can I use plus-aliases in the format address+keyword@mailbox.org?

How can I choose which alias to use as a sender address?

What happens if an alias gets deleted? 

May I use aliases that contain external domain names, such as my.name@gmail.com?

Can I migrate an existing alias into a dedicated mailbox?