The Post Office Protocol 3 (POP3 for short) is a method for receiving emails.
POP3 is a transmission protocol that allows an email client to fetch email from a server.
POP3 is the right choice if online time is important to you for cost reasons. With this procedure, the emails are always transmitted from the server to the local device. Even if you only receive and read your emails on a specific computer, you can use POP3 without hesitation.
However, if you want to manage emails online and access your email account from different devices, IMAP is the right choice.