How does mail work on Bitrix?

Question

CMS

Good day to all!
Dear forum users! I ask for your advice.
I can’t understand how Bitrix works on our online store.
There are settings for the online store module, there is mail for this module (see screenshot). My address is making a test order and it comes from this e-mail that I write in the module settings.
Hence the question - how? I do not specify the password and ports for the mailbox. But at the same time, the sender's address is here, which I will indicate.

Answer 1

When sending mail, you can specify any sender, although [email protected]
RFC does not prohibit this.

Answer 2

Thanks everyone for the replies! I found the answers. By default, Bitrix uses php send to send emails.