The defendant in a lawsuit must be served (delivered) a summons or citation (an order from the court to appear and answer the lawsuit) and a copy of the lawsuit (1) to provide due process (fairness) by giving the defendant notice of the lawsuit and the opportunity to appear in court and defend the lawsuit; and (2) to give the court personal jurisdiction (authority) over the defendant.

In Kentucky, as in all states, the due process clause of the Constitution requires that a defendant in a lawsuit be properly notified of the legal action against them. This is accomplished through the service of a summons or citation, along with a copy of the complaint or petition filed with the court. The summons informs the defendant that they are being sued and provides instructions on how to respond to the lawsuit. Service must be carried out in a manner prescribed by law to ensure that the defendant is given a fair opportunity to appear in court and defend themselves. Kentucky Rules of Civil Procedure (CR) outline the specific methods by which service can be made, such as personal delivery to the defendant, leaving the documents with a resident of suitable age and discretion at the defendant's dwelling, or by certified mail, among others. Proper service of process is also necessary for the court to establish personal jurisdiction over the defendant, which is the court's authority to make legal decisions affecting the defendant. If service is not properly executed, the court may not be able to hear the case, and any judgments made could be voided.