Hey there @Hugo41701 - thanks for your topic, and great question! Firstly, check out our New User Guide - it’ll def prove helpful as you get used to the platform!
As you know, we have integrations with both Stripe and PayPal. You can connect your Stripe or PayPal account to Calendly to collect payments when your invitees schedule with you. If you don't use these services, you could add a custom link to your confirmation page that leads to your preferred payment provider. You could also customize your invitee notification emails to include that link!
Because the payment collection takes place via PayPal and not Calendly, Calendly has no access to the information needed to create an invoice. You will need to create invoices manually or with tools provided by PayPal (or perhaps another third party tool that you can implement) in order to meet this goal. I’m sorry for the inconvenience - I really do not like having to say “no”!
I hope this helps!