Here recommend you a professional tool - iPhone Data Eraser or iPhone Data Eraser for Mac, the iPhone Data Eraser can thoroughly delete the data from your iPhone, and can never be restored. whether it is a junk mail Or the secret e-mail that you want to immediately delete can be completely removed. Download a free trial version, give it a try!
Note: Please remember to backup data from iPhone to PC or iTunes/iCloud before wiping your device, so that you can still restore the data you wanted when you need.
How to Delete Emails on iPhone Permanently
Step 1. Connect your iPhone to computer
|Connect your iPhone to computer|
Step 2. Choose "Erase All Data on Device" in the window of program
|Choose the iphone data you need delete|
|Start to delete the iphone data|
|Complete the cleaners|
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