Several Api services available for backup your wordpress blog on cloud storage. But i prefer, Google Drive to store your files and database backup. Drive is Google product and allow users 5GB free of cost.
Now, coming to our topic, Download and install “Google Drive for WordPress” from WordPress plugin repository.
After installation, you will find out “Configure Google Account” tab on your wp-admin panel.
For connecting WordPress blog with your Google Drive account,You need Google API Console to generate Client Id & Client Secret Key.