It can be a long and tedious process, scroll through your inboxes, tap each email individually so you can delete it. So far, Apple has not introduced a 1-button solution to the problem. Luckily for us, there’s a workaround, and that doesn’t involve installing backups or resetting your iPhone or iPad in any way.
Move Important emails to a safe folder
Before we get started, we need to make sure that all our important emails are stored in a separate folder, so that they don’t get deleted by any bulk action.
Place any emails you want to keep in the new folder. Create a folder whatever you like. After that, it’s a simple three-step process.
ALL DELETING EMAILS Go to your inbox, Tap Edit, then Mark All, and then Mark All as Read. This will then close the Edit mode.
Tap Edit again, and click the top message in the inbox. Press and hold the move with your thumb. While holding down the Move button, uncheck the top message, and then release the Move button. If you have a large number of emails in the inbox, wait a few seconds without touching your screen.
After a few moments, you’ll be taken to the Move screen. This will allow you to bulk move all selected emails. You can move your important email to any of your folders. In this case, we will move them to the ‘Trash’ folder.
Note that this solution is also Gmail inbox, as is for iCloud accounts, so give it a try!