Hello @secbug1101 thanks for your post. That appears to be a booking site from Appointments.
(If you see the URL, you'll notice the path...https://squareup.com/appointments/book/...)
Do you currently use Square for your business? If so , you should be able to access your online Dashboard where you can enable appointments. Here is some info about creating an online booking page...
https://squareup.com/help/us/en/article/7245-create-a-square-online-booking-site-from-appointments
https://squareup.com/help/us/en/article/5354-square-appointments-guide
And some more info is available here. I hope this helps answer your question.
