How to send an invite to Appointment with WP Mail3

Hello^^

I am an IT student and I am currently working on a small project.

On my website, users can fill out a form that was created with Contact Form 7. I have already successfully implemented that the contents of the form are sent and receive the generated data as intended.

Among other things, the form contains a time span that serves as a reservation. My aim is to send this time period as an appointment. I have managed to create an .ics file with a script and send it as an attachment. However, the file is actually only sent as an attachment instead of as a direct invitation that is displayed in the recipient’s calendar, for example.

I would be very grateful for any support or ideas.

Many thanks and best regards
Hurloc