1. Navigate to myaccount.google.com.
2. Click Manage your data & personalization under Privacy & personalization.
3. Scroll down until you reach Download or delete your data.
4. Select Download your data.
5. If you simply want to download your Gmail, go to the top of the page and click Deselect all.
6. Scroll down to Mail and tick the box under Select data to include.
Two buttons will appear.
One is titled Multiple formats; click on it to see which format(s) your data will be downloaded in.
The other will most likely be titled All mail data included; select that if you only want to download particular categories.
7. Scroll down and hit the Next step button.
8. Click the arrow beneath the Delivery method to see your options, which include emailing a download link or adding it to your Drive, Dropbox, or OneDrive.
You can also select whether to export once a month or every two months, as well as the type of file and the maximum file size.
9. After you've finished selecting your choices, click Create export.
Your export will begin, it could take days to complete. You may either select Cancel export or Create another export if you want to.