To change iOS 11 Mail settings on automatic deletion of messages for your email account take the following steps:

• Open the Email application Select Settings from the navigation bar.
• Select Account Settings from the drop-down menu.
• To configure an account, tap it.
• Select More Options.
• Incoming settings should be tapped.
• Look for it towards the bottom of the page. Remove emails from the server
• Select When I delete from Inbox from the drop-down menu (the same way you would if you were initially setting up the account)

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