Add public scheduling to Odoo
Here is a great free app compatible with Odoo 12 to allow public users to book appointments easily using the app s2u_online_appointment.
By default only registered users can access the /online-appointment page.
However, if need public users to have access, then need to do the following:
Enable developer mode.
Go to Technical > System Parameters.
Then Create new parameter with name: s2u_online_appointment
and value: public.
Save it.
Voila, now public can use (with all the usual caveats about that of course).