Calendar invites not sending to invitees

MvP217 wrote:

How is this still not fixed, Apple?

There appears to be nothing broken - to me.

Here is the appropriate reference from the iPhone User Guide:

https://help.apple.com/iphone/12/#/iph82c5721ca

As it says there:

"iCloud, Microsoft Exchange, and some CalDAV servers let you send and receive meeting invitations."

You have not told us where you house your calendar. Perhaps you do not use one of the above methods.