Which protocol is used for sending emails, according to iOS mail settings?

The protocol used for sending emails, particularly in the context of iOS mail settings, is SMTP, which stands for Simple Mail Transfer Protocol. SMTP is the standard protocol for sending outgoing emails over the internet. When you configure an email account on iOS devices, SMTP settings are necessary to allow the device to transmit emails to the recipients’ mail servers.

While POP3 and IMAP are protocols primarily used for receiving emails, SMTP functions specifically for sending them, which is why it is the correct choice in this scenario. HTTP is used for web communication and is not relevant for sending or receiving emails. Understanding these distinctions helps clarify the specific roles each protocol plays in email communication.