Welcome to Android Central! I'm going to take a guess that you're talking about your mail server so that you can add your mail account to the stock Email app. It really depends on what email service you want to add. In general, if it's a webmail account like Hotmail or Outlook.com, you should go to that site and do a search in the Help area for "server settings." If it's an exchange account (i.e., an email account associated with your work that requires you to use Outlook on your computer), then you should ask your company's IT department.