Internet message access protocol allows you to access your email messages wherever you are. Email messages are stored on servers. Whenever you check your inbox, your email, client contacts the server to connect you with your messages. When you read an email address using IMAP, you aren’t actually downloading or storing it on your computer instead you are reading it off the server.
IMAP ports are 143 for the default non-encrypted and port 993 to connect using IMAP securely.