Hey there, @DrLuc - great question! Firstly, check out our New User Guide - it’ll def prove helpful as you get used to the platform! Check out our Company Admin Guide as well.

While I’d usually suggest our Workflows feature, which allows you to set up followup emails to be sent to all invitees for specifically selected event types, this isn’t going to work retroactively (you won’t be able to go in, set it up and have it fire off to all past invitees of an event type). At this time, there is not quite a way to do this within Calendly itself, however, you should be able to use a third party tool like Zapier to make this happen with a CRM or manual email. 

In order to get all the data you need, integrate Zapier with Calendly so that all invitee info starts being pushed to Zapier upon booking. Then, have that sent to a spreadsheet - and set up the spreadsheet to either push to a CRM or use it yourself to pull data from in order to send out this email to your historical invitees.

I hope this helps! I know it’s not perfect, but it should work!