Communications

Sentient beings have spent a lot of time figuring out how to talk to each other over long distances. Over the years, two primary means have been developed.

Comms
Comms are based on electromagnetic frequencies, most common communicators, or "comlinks" have a range of several miles. Many planets and systems have built comm networks that extend that range around the planet, or even to neighboring moons and planets.

Holonet
One of the great works of the Old Republic that is constantly being expanded on and upgraded, the holonet is a series of satellites and relays that send communications nearly instantly across the galaxy by utilizing the unique properties of "subspace", a quantum dimension that overlaps the physical dimension, much like hyperspace. Holonet transmissions only function in space, so planetary holonet access is achieved by having transceiver that converts the transmissions to a dedicated comm channel. Since holonet transcievers are bulky and very expensive, most are installed in starships or in their own dedicated buildings and communication hubs. Generally, if you want to send a message to someone across the galaxy, you'll record the message and send it to another holonet transceiver where someone with the proper ID can listen to it. Depending on who owns the transceiver, there may be costs associated with sending or receiving a message.