A Practice Note explaining how to prepare, file, and serve a summons, complaint, and other case-initiating documents (service of process) in a civil suit in Illinois circuit court. This Note describes how to file an action electronically and in paper format (where allowed). It also sets out the steps that counsel must take when serving process on an individual, corporate, or other organizational defendant by personal service, substitute (abode) service on a family member, service on the Secretary of State, or service by publication, how to prepare proof of service (also known as a return of service), how to serve defendants located in other US states or foreign countries, and how to request a waiver of service.