Vodafone supports two types of email:
IMAP (Internet Message Access Protocol)
This is the option we recommend as it means your emails are 'in the cloud' and can be accessed by more than one device. Your emails synchronise across all your devices as they are managed on the email server.
POP (Post Office Protocol)
POP is from a time when you would access your email from one device only i.e. your PC. It simply downloads email to your device and then (but not always) deletes the email from the server.