What is POP3?
Post Office Protocol v3 (POP3) is a standard mail protocol used to receive emails from a remote mail server to a local email client. POP3 allows you to download email messages on your local computer and read them even when you are offline in programs like Outlook and Outlook Express.
What is IMAP?
The Internet Message Access Protocol (IMAP) is a mail protocol used for accessing email on a remote web server from a local client. IMAP and POP3 are the two most commonly used Internet mail protocols for retrieving emails. Both protocols are supported by all modern email clients and web servers. Any e-mails downloaded from the server using your IMAP account will remain on the server, a local copy will not be stored on your PC and in most cases you will need an active internet connection to read your emails.
Main difference between IMAP and POP3:
The POP3 protocol assumes that there is only one client connected to the mailbox. In contrast, the IMAP protocol allows simultaneous access by multiple clients. IMAP is suitable for you if your mailbox is about to be managed by multiple users or if you want access to your email from your PC and mobile device while on the go.