Cannot get what email? Yahoo Mail, Hotmail, outlook mail or pop email from your ISP? Information would be great.
The native email app on devices are not that great. If you have mail accounts on the above listed mail providers (except pop email) you can download the stand alone apps from the Apple Store and all that is needed is your login name and password.
Pop3 email must be set up via your ISP help department. Many list the server settings for pop3 and SMTP to get your email up and running.