Click Save Changes and you're done.
Also rolling out to new Gmail users are Nudges, which highlight messages that Google thinks you've either forgotten about (ahem, ignoring) or need to reply to. Previously this feature was available for Chrome users as an add-on for the browser, but this naturally hinders performance like most add-ons.
Administrators of corporate services G Suite to activate the feature should turn on the "Gmail offline web", and regular Gmail users are already beginning to access the new mode, which is very useful in traveling or in an unstable Network. The new in-built offline feature is certainly an upgrade and is a boon for users who would like to stay productive even in areas where they expect to be limited or no connectivity. Knowing it's there, however, could help you make the most of time you might otherwise not be able to get work done, though. When users choose to keep it, the data will not be deleted from the computer once they sign out of their Google account.
Go to the settings page where you will find an option for "Offline".
On the Offline menu click Enable Offline Mail and you'll see a screen with several options on it (Figure C). Gmail is going to need some time to download all those messages.
Anything you do in Offline mode will sync whenever you manage to get back online. The last setting is Security and the ability to set whether Gmail keeps or removes offline data on your computer after logging out. Note that this is only available for the web version of Gmail and it is unclear if there are plans to bring a similar feature to mobile in the future.
To delete stored email clear your internet history with the option to delete Cookies And Other Site Data checked (Figure D).