Adding Folders to Email App

I would like to be able to store some emails in separate folders so that they don't disappear once they've gotten too old and fallen beyond the 200 email limit I have in the email program settings. It would also help in organizing some emails around specific topic areas. I know how to move emails, but haven't been able to figure out how to create new folders.

I get email through a cable based, high speed Internet Service Provider (Road Runner). It's a POP3 type account. Right now I have the following 4 folders on my Iphone for email: Inmail, drafts, Outbox, and Sent. I've created some folders in my in box in the web based program for Roadrunner, but they don't seem to carry over onto my Iphone.

Any suggestions/help would be appreciated.
Thanks,
Gerry