Hi Lenny,
You can create appointment/event/meeting in your calendar event via below API
https://docs.microsoft.com/en-us/graph/api/calendar-post-events?view=graph-rest-1.0&tabs=http
If you hit this API with proper request, meeting will be created in your calendar
HI,
It can be done using https://marketplace.mendix.com/link/component/315 this widget and you can use Microsoft graph api logic for appointment creation.
Suggest you to refer this doc https://docs.microsoft.com/en-us/graph/api/resources/mail-api-overview?view=graph-rest-1.0