POP3-(post office protocol 3)
1.It is used for retrieving email from an email server.
2.It is download the email to your device from a mail server and only download inbox's email.
3.In pop3 , the email is deleted on the mail server once it's downloaded to a device.
4.It does not sync folders.
5.In pop3,downloaded email is viewable without an internet connection.
6.POP3 saves storage space on the mail server.
Disadvantages:
1.We need a backup plan for our email incase device crashes or is lost.
2.Device is more vulnerable to viruses since the emails are fully downloaded.


IMAP- (Internet Message Access Protocol)
1.It allows you to view your email, that is on the server, from multiple devices.
2.It caches local copies of the email onto all of your devices.
3.It does sync folders.
4.All the email is stored on the server.
5.We are able to see all our email including sent items,drafts,deleted items and any custom folders.
6. All the emails and folders are synchronized.
Disadvantages:
1. Email is not viewable without an internet connection.(because IMAP only caches local copies of the email on your device instead of downloading them.)