how to delete all mails in Gmail at once?
Delete All Messages. To delete all of your emails, open the Gmail web interface, log in to your account, and choose “Troubleshoot problems”. In the drop-down menu that appears, click “Empty Trash.” Delete everything from it as directed.
Open the folder where you saved the emails you wish to remove in the Gmail app for Android. Tap the icon to the left of each email that you want to delete or long-press it to select it. In the upper-right corner of the screen, tap the Delete symbol.
Delete large attachments. Delete entire categories. Unsubscribe from annoying lists. Allow you to block unwanted senders.
Go to Gmail on your computer. Check the box in the top left to select all messages. Select all conversations if you have more than one page of emails. Delete is the top option.
Open Gmail on your computer. Check the box in the top left corner to select all of the messages on the page. Select Delete from the drop-down menu.
