Two particles interact with each other and get linked in a manner that measuring one particle allows us to instantaneously know what the other particle will be irrespective of the distance between them
Einstein (EPR) thought the particles had hidden variables and called this spooky action at a distance. But since then it has been shown through experiments based on the Bell inequality test that this is not true and non locality exists.
After entanglement, the particles do not remain distinct entities and are described by the same wave function. So it makes no sense to theorize that they are communicating across a distance.