How can I add optimum email to my iPhone mail app?

This process is valid for all mails, AOL, Google, Yahoo, Outlook, Hotmail, Exchange etc etc

1. Keep your email id and password handy
2. Use this link to find out your Incoming and Outgoing server settings by entering your email address

https://support.apple.com/mail-settings-lookup

If it is not available in the link above contact your email client

The GIF is self explanatory.

iCloud Account IMAP and SMTP