Should I use Pop3 or IMAP?

There is no right or wrong answer; this depends on your needs.

Pop3 simply downloads your full emails to the email application (email client) and removes the email from the server (unless otherwise specified in the advanced settings). This option is good if you only check your mail from one computer and you do not use webmail to check the particular email account you are setting up.

IMAP allows the email application (email client) to display the emails that are on the server and does not download and remove them from the server like Pop3 does. If you check your email from different computers and you want them all to show the same information or if you check you use webmail in addition to an email application then this is the choice for you. IMAP also synchronizes your instantly. For instance, if you have your email open on two different computers and you delete an email on one of them it will automatically delete that email from the other computers email application as well. One drawback of IMAP is that you cannot view your emails offline. By default you must be online to read any of your previous emails.