Magento Open Source 2.1.x

Magento 2.1.x Notice: Magento 2.1.18 is the final 2.1.x release. After June 2019, Magento 2.1.x will no longer receive security patches, quality fixes, or documentation updates. To maintain your site's performance, security, and PCIPayment Card Industry: Refers to debit and credit cards and their associated businesses. compliance, upgrade to the latest version of Magento. The Magento User Guide 2.1.x remains available in PDF for Open Source and Commerce.

Google API

Stores > Settings > Configuration > Sales >Google APIApplication Program Interface: A software interface that lets third-party applications read and write to a system using programming language constructs or statements.