Otherwise the calendar server should send them, but this does not work for me on my apple calendar and, based on the support topics I read, many others have problems with it.
Yes unfortunately due to whatever reason “the iCloud calendar server just doesn’t seem to send meeting invites” even though eM Client passes the invite to the iCloud server. Some server related issue.
@Gary gives a good “gui example below” of what you describe using eM Client local calendar as an alternative way of sending calendar meeting invites.
https://forum.emclient.com/t/calendar-invitation-are-not-sent/45308/54
Note: I personally with my Mac just setup separate Google calendars and Microsoft calendars and then added those calendars manually into eM Client.