The connection to Google services for G Suite (GDrive/Gmail/Calendar) is done through the following process. This is connection process using he API for Spirion to Google - https://my.spirion.com/help/enterpriseconsole/index.htm#3594.htm?Highlight=google. You must use the Google Admin Authorization account, this account cannot be an account that has user roles such as GDrive, etc.
When downloaded to the desktop you can view its Tag (Data Classification) using Windows Explorer.
When a file is sent through Gmail and saved to the desktop you can see both the icon overlay which depicts the data classification, by viewing the file properties (right click) tab, or by opening the file to view the classification which is displayed in the Ribbon or menu options.