What do you need to run 2 sites from 1 database?

Question

Software design

The task was received: there will be a food delivery site, most likely wp, as well as a delivery operator window (the second site for react). It is necessary that when the user makes an order (in WP) in the operator window (react), it is immediately displayed.
I can’t find the info on how to connect react to vp so that vp “knocks” react when ordering.
Interested in any solutions.