Four steps, and none of them is the design work. Pick the design the example is shown on. Put your two names and the date over the ones in the hero. Set the place line to the precision you can promise — a venue if it is booked, a region if it is not. Then check the add-to-calendar button, because whatever the time row says is what lands in a guest's phone.
Then send the link wherever you already talk to these people. There is nothing for a guest to install and no account for them to make, and the page stays editable after it has gone out — so a place line that says "region" today can say the venue in March without a second message.
Designing it costs nothing — the announcement builds free, and the first 10 guests can open it before any money changes hands. Taking that limit off costs $19 once, whatever the guest count, hosted through your wedding date and at least 90 days after. A second language, as in the Arabic example above, adds $10. The picker only offers designs this SKU is actually sold on, so anything missing from it is not something you are overlooking.
The full invitation is the same link later, with the RSVP, the schedule, the gallery and the map switched on. It is $49 at checkout today — $89 list, with the discount that is running until Oct 31 applied automatically — and going up to it is billed as the gap between the two figures rather than as a second purchase. That move is made by hand at our end, so do not go looking for a button.