IMAP email is a type of email service which keeps emails stored on the server (our end). This allows you to synchronise email across several different devices, and you’ll always be able to access all your emails. IMAP is what we use for our email hosting.
POP works a little differently: it downloads the emails onto your device and then, in most cases, removes them from the server. This means that once you’ve download an email on one device you can’t get the same email on another device – as it’s has been deleted from the server. This is why IMAP is the preferred way of getting mail across desktop, tablet and smartphones.