Definition– service of process is the procedure by which a party to a lawsuit gives an appropriate notice of initial legal action to another party, court, or administrative body in an effort to exercise jurisdiction over that person so as to enable that person to respond to the proceeding before the court.
Service of process is the procedure necessary to make the other party to a lawsuit aware that the lawsuit is occurring, so that the opposing party can be prepared. Typically it involves giving them papers containing the case information, or publishing the information in some way.
Jake is planning to sue Alex for failing to abide by a contract the two created. Jake filed the appropriate complaint with the court alleging how the contract was broken by Alex. Jake then must serve a copy of the complaint to Alex, so that Alex is properly prepared to argue the breach of contract case.