IMAP stands for "Internet Message Access Protocol" and is a protocol for receiving email. This protocol requires a stable Internet connection. IMAP allows you to access your mailbox in real time with an email program of your choice. Any actions (e.g. delete, move an email etc.) will be conducted directly in your mail.com mailbox. This means that you can access your email on another computer, a smartphone, or at https://www.mail.com/ at any time. The status of your email is the same on all devices.
SMTP stands for "Simple Mail Transfer Protocol" and is a protocol for sending email. SMTP transmits your email from your email program to a server and then forwards them to the respective recipient.