What is the legal term for the initial document that formally accuses someone of a crime?

The term that appropriately describes the initial document which formally accuses someone of a crime is an indictment. This document is typically issued by a grand jury and contains the formal charges against an individual accused of a crime. An indictment is significant because it represents a determination that there is enough evidence to formally accuse someone and proceed with prosecution.

While other documents such as an information or complaint relate to criminal charges, they are produced through different processes. An information is usually filed by a prosecutor without the need for a grand jury, and a complaint is a basic legal document that initiates a civil suit or can refer to a lower-level infraction. A warrant, on the other hand, is a legal document that authorizes law enforcement to carry out an arrest or search, not to formally accuse someone. Hence, an indictment is the correct choice as it specifically pertains to the formal accusation of a crime, thereby making it the most accurate answer.