Step-1: Open your Google Chrome Browser and then open this ( Gmail Offline) on your Google Chrome Browser.
Step-2: Now just download the app and clicking on “Add to Chrome”. Then it will start installing.
Step-3: After installing the app, you will get access to Gmail Offline version in your Chrome Browser without the internet.
Step-4: Now this Gmail Offline version will start showing on your Chrome apps section. Just launch the Gmail and just click “Allow”.
Step-5: Now, it will take some minutes to synchronize your all emails in your Gmail online version and it will be stored in your Offline Gmail version. Remember if you have many emails pending on your Gmail account then it will take a long time to store on your local PC.