Add attendees to shared calendar event

I am looking to create event’s and let everyone create events on a shared calendar and add attendees

You should be able to create a new calendar and share it with writing permissions to others:
https://docs.nextcloud.com/server/stable/user_manual/en/groupware/calendar.html#sharing-calendars

I created it and shared it with the option “can edit” enabled for the whole group, but they are not able to create appointments, make an event, or add attendees.

Which version of NC?
Do they get an error, don’t they have this option in their interface, do you have errors in the logs?

We are on version 27.1.6 they do not have the option to add attendees

only a "Find a time " button that can’t be pressed also

It looks like this option was removed (issue):

But some need this feature back:

(you can give it a thumbs up to support it)