We all knows Google has many products like Gmail, Drive, YouTube, Contacts, Calendar, Photos, Google+ and Docs. We can access and use all google products with one google account. So, our data is stored in different products that are using by us. But Google provide a feature to Download Your All Google Account Data At Once from one place.
After that Click on Create Archive. It takes longs time to create archive. When archive is created, The link of Zip file of your all data will be sent in your email inbox. You can also choose different delivery methods (Add to drive, Add to Dropbox, Add to Onedrive).