IMAP stands for Internet Messaging Access Protocol. It is an email protocol that supports email message management and retrieval from the receiving server.
Since IMAP is used for message retrieval, it does not support sending mail, merely accessing it. Hence,you are unable to send email using the IMAP protocol as it is utilized to receive emails.
IMAP enables you to access, organize, read and sort your email messages without first downloading them. As a result, IMAP is extremely quick and efficient. The server also preserves a record of all of the messages that you send, allowing you to access them anywhere.
POP3 is another email receiving protocol that stands for “ for Post Office Protocol. The number three refers to “version 3,” the most recent and extensively employed version — hence the name “POP3.”