POP: acronym means Post Office Protocol. This means that you access your email account using a device, you see an email and you click on it and it downloads this email to that device. Same like going to the Post Office and fetching your mail. You collected, it’s yours. Or better, that device.
Note: If you are using multiple devices, your email is delivered to all these devices.
IMAP: acronym means: Internet Mail Access Protocol: meaning all emails are stored on a server on the internet (a cloud server) and can be accessed by any device.
If you plan to view your emails from multiple devices (laptop, tablet, smartphone) and plan to manage your mailbox size then we recommend using IMAP. If you are simply using one email app or device (such as Outlook or Mac Mail) or you don’t want to worry about mailbox quota then we recommend POP.