This procedure is applicable for deleting email accounts from iOS devices (iPhone, iPad, etc.) running iOS 6 or higher. The screenshots shown below were taken from an iPhone 6 running iOS 8.0.2. Other devices will be similar.
To delete an email account on an iOS device, perform the following:
1. From the home screen, tap Settings.
2. Tap Mail, Contacts, Calendars.
3. Tap the Account or Service Name to remove (Google, G-Suite, Exchange, IMAP, Etc.). Whatever name you used for this account.
4. Scroll down and tap Delete Account.
5. Tap Delete from My iPhone to confirm. Note that other types of iOS devices will display similar confirmation notices.
6. If you intend to reconfigure the same email address, we recommend that you restart the iOS device before attempting the reconfiguration. Hold the lock button down and slide the dial right to power off the device. The power up the device and proceed to the article listed below.