Calendar invitations vs. Email notifications
There are two types of notifications invitees can receive when scheduling with you: a calendar invitation (recommended) or an email confirmation.
A calendar invitation is sent directly from your calendar. Your invitee is added as a guest to the event and the event is automatically added to their calendar as well. This feature is only available to Google, Office 365 and Outlook.com users, and it can not be enabled for group event types.
An email confirmation includes your photo or logo, and gives invitees the option to add the event to their preferred calendar: