What is the difference between POP and IMAP?

If you are setting up your email software (e.g., Outlook, Thunderbird), you must indicate how you want to receive email-either with a POP connection or an IMAP connection. IMAP is quickly becoming the preferred method, since it gives you complete access to all email and all email folders, from multiple computers or mobile devices.

POP

When you check your email with a POP connection, new email messages are downloaded to your computer and are then deleted from the email server.
Access: Since your email is stored on your computer, you must be at your computer to access your email.
Storage: You don't need to worry about running out of online storage space. Since you're downloading your emails to your computer, you can keep as many emails as your computer can store.
Backup: You should implement an effective backup system for your computer, in case you need to retrieve lost or deleted emails.
Internet Connection: You will need an Internet connection to download email, but you can view your downloaded email offline (i.e., without an Internet connection).

IMAP

When you check your email with an IMAP connection, you are accessing and managing your email directly from the email server.

Access: Since the emails are stored on the email server, you can access and manage your email and email folders from multiple computers or mobile devices.

Storage: If you have limited online storage space, you may need to delete some emails periodically to avoid exceeding your storage capacity.
Backup: Email is automatically backed up every evening; so, if you accidentally delete an email, your email administrator can retrieve it - even up to 14 days later.
Internet Connection: If you do not have an Internet connection, you cannot access your email.
Note: By default, email software applications (e.g., Outlook, Thunderbird) store your sent, draft, and trash email on your computer, rather than storing it on the email server (as it should with an IMAP connection). You may need to make some adjustments to your email software setup so that sent, drafts, and trash email will be stored in your online Sent, Drafts, and Trash folders.