Use this when the user wants an actual Lemonvite invitation or RSVP page for an event, party, celebration or gathering: create an invitation, make an invite, set up RSVPs, or use an invitation image created or selected in this conversation (pass it as invitation_image). It creates a DRAFT only and does not publish, charge, or contact anyone during this call. Optional invitation_image downloads and stores the supplied artwork; optional reminder_date schedules a later email to the host through the reminders service. Do not call it merely because invitation wording or images are being discussed. Required: title, event_type, start_datetime, timezone and, for in-person events, location_name (a venue name; the address is optional). Everything else can be added later with lemonvite_update_invitation. If a required detail is missing or invalid, nothing is created and the error names the field to ask the user about. Next steps: lemonvite_add_guests to invite people, then lemonvite_publish_invitation to go live (lemonvite_start_checkout first if payment_status is payment_required).