Its acronym IMAP “Internet Message Access Protocol”. It is known as an Internet message access protocol. Which; it is a method of accessing emails on a server without having to download them to your local hard drive. It is the main difference between IMAP and another popular email protocol called " POP3 ".
POP3 users must download messages to their hard drive before reading them. The advantage of using an IMAP mail server is that users can check their mail from multiple computers and always see the same messages.
This is because the messages remain on the server until the user chooses to download them to their local drive. Most of the webmail systems are based on IMAP. This allows everyone to have access to sent and received messages, no matter what equipment is used to check the different email inboxes.
Mail client programs, such as Microsoft Outlook and Mac OS X Mail, allow you to specify what type of e-mail server protocol you are using. If you use your ISP's mail service, you should check with them to find out if their email server uses IMAP or POP3.
That is to say; They are standard Internet protocols for e-mail that allow your e-mail program to access the e-mail accounts on your web space. This allows multiple clients to access the same mailbox, facilitating later access to the email messages available on the server via webmail.