Can I invite people to meetings using Calendar if they are not in my Contacts app?

I read this page:

https://support.apple.com/kb/PH20311?locale=en_US&viewlocale=en_US

It seems to suggest that if I don't have the contact in my address book that I won't be able to invite them to an event.

But this can't be true, can it?

I have a new business contact that I would like to invite to a product demo using Calendar.

Is this possible? I don't want/need to actually add this person to my Contacts app, I just want to set up a meeting.

Please someone help me understand how best to do this on my Mac.

Thanks!