Attached Calendar Events (ICS)
(Please note: for a more polished calendar experience, check out the standalone Google Calendar Integration included on Pro & higher plans. That sends actual calendar invites from your Google Calendar account.)
You can generate an ICS file attachment for that works with any calendar system (Outlook, gCal, iCal) and you can modify the subject of that calendar event title from Scheduling >> Emails >> Details. Scroll down to this box:
What Do Participants See Exactly in the Calendar Invite?
The content of the details email will display inside any downloaded ICS calendar invite—and can be edited from Scheduling >> Emails >> Details. That's what shows up in the description section (see screenshot below) and this will be reflected in what the participant sees in their ICS invite.
You can switch the Details email to "Never", so participants do not receive the second email on confirming their scheduled time slot.