Email invitations via Google Calendar
If you add attendees to an event and check “Send invitations”, the attendees will automatically get an invitation by email with links that they can click to respond with “Yes”, “Maybe” or “No”. If an attendee also uses Google Calendar, the event is also automatically added to his calendar. Please see the description under “Sending invitations to attendees” here: EditEmail invitations as ICS attachments
If you get an invitation by email that contains an attached ICS file, you can import it into CalenGoo and create a new event from it. Just press the attachment in the email until “Open In…” appears:Then select “Open In…”, choose CalenGoo, modify the new event if necessary and tap “Save” to save it into your calendar: