Can I invite my guests using WhatsApp/Messenger/Instagram/Telegram?
The way of sharing your website, at its core is your website address (https://sayi.do/yournameshere). This is the like the street address to a location in that it is unique to one thing, website in this case. It can be shared on any platform, including WhatsApp and any other messaging application.
If you want to send the invitation rather than the website address link, you can copy the image that is created for your email invitation. It is shown to you on the last step of the Email Announcement creation process. Once the image is copied, you can paste it directly into WhatsApp.