If you use an email provider like iCloud, Google or Yahoo, Mail can automatically set up your email account with just your email address and password.
Go to Settings > Mail Tap Add Account, then select your email provider.
Enter your email address and password. Tap Next and wait for Mail to verify your account. Choose information from your email account, like Contacts or Calendars. Tap Save.
There are several types of popular accounts that are easy to set up on the iPhone. If your email account belongs to one of these mail providers, click on its icon, the system will connect to the selected service and ask for your email account or username and password. If your email account does not belong to any of the services that appear click on "Other".
When you set up an IMAP account in your iPhone you keep a copy of the emails in the cloud, that is, in the mail server.
If you delete an email or move it from a folder in your Apple iPhone that change will also occur on the server and therefore on all devices that are configured with the same email account.
If you set your Apple with a POP or POP3 account, the emails are downloaded to the device and can be deleted, read or changed without affecting the other devices that have the same email account.
Usually this configuration is used for shared accounts in which several people want to keep the emails that have been read by others as NOT read or for those who have the email in the mobile and on the computer and do not want the changes to be reflected in the other device.