POP3 (Post Office Protocol) and IMAP (Internet Message Access Protocol) both are email services used to receive emails via an email client or device.
If you want to decide to download emails from the mail server you can use a client or device, client or device will contact with the server and then it will download your mails to local storage. After that you will have access to emails even without internet.
POP3
While using POP3 all of the mails are downloaded from the mail server to local storage. Now your mails are available on your device or client. But it will remove mails from the server, that means you cannot get access to mail box from anywhere.
- Pros
Mail is always available to the device even if you are offline.
- Cons
Only view messages form inbox.
Once messages are downloaded it will remove them from the mail server.
IMAP
Internet Message Access Protocol (IMAP) simply connects to the mailbox and allows you to select the mails you want to download. Through this, you can manage multiple clients. It also keeps a copy of mail and one can access mailbox from anywhere.
- Pros
One can manage multiple clients.
Allows to whom the mail will download.
- Cons
It can delay downloading large emails especially mails with attachments.