For more information about the technical aspects of how Fieldnotes is integrated to your email and calendar account, here are details:
Microsoft O365: https://docs.microsoft.com/en-us/graph/overview
Google Gmail: https://developers.google.com/identity/protocols/oauth2
Using these services, we integrate and push calendar events and tasks as well as emails to be sent through this integration. This enables you to have the convenience of having calendar events to be sent from within your CRM.