POP3 (Post Office Protocol version 3) and IMAP (Internet Mail Access Protocol) are two protocols that are used to retrieve email messages from a remote server.
The main difference between the two protocols is how they handle email messages on the server.
With POP3, when you download an email message using a client like Microsoft Outlook or Mozilla Thunderbird, the message is downloaded from the server and then deleted from the server. This means that once you download a message using POP3, it is not available on the server anymore.
IMAP, on the other hand, leaves the messages on the server and synchronizes the email client with the server. This means that if you read a message on one device, it will be marked as read on the server and on all other devices that are connected to the server using IMAP. This makes IMAP better for people who use multiple devices to access their email, as it allows them to keep their messages in sync across all their devices.
In summary, the main difference between POP3 and IMAP is that POP3 downloads email messages from the server and removes them from the server, while IMAP leaves the messages on the server and synchronizes the client with the server.