Forgery is the criminal offense of making or uttering a false document or other instrument with the intent to defraud or harm someone—including a written or printed document, money, coins, tokens, stamps, checks, cashier’s checks, bonds, money orders, traveler’s checks, real property deeds, contracts, stock certificates, lottery tickets, wills, seals, credit cards, badges, trademarks, and symbols of value, right, privilege, or identification. Uttering a document means to declare—either directly or indirectly, and through words or actions—that the document is legitimate and what it purports to be.

Forging a document includes altering, making, completing, executing, or authenticating a writing so it purports (1) to be the act of another who did not authorize that act; (2) to have been executed at a time or place or in a numbered sequence other than was in fact the case; or (3) to be a copy of an original when no such original existed.

Forging a document also includes the acts of issuing, transferring, registering the transfer of, recording, passing, publishing, or otherwise uttering a document that is forged. And in some states the mere possession of a forged document with the intent to utter it constitutes forging a document.

The definitions, penalties, and punishments for the crime of forgery vary from state to state and are generally located in a state’s statutes—often in the penal or criminal code.

In California, forgery is defined under Penal Code Section 470. It is a crime that involves the creation, alteration, or use of a false document with the intent to commit fraud. This includes signing someone else's name, faking a seal or other official endorsement, changing or fabricating legal documents, and presenting any of these as true when they are not. The act of uttering a forged document, which means offering it as genuine, is also considered forgery. The law covers a wide range of documents, including checks, bonds, money orders, contracts, and legal certificates. Forgery can be charged as a misdemeanor or a felony in California, depending on the circumstances and the value of the fraud. Penalties can include imprisonment, fines, or both. Additionally, possessing a forged document with the intent to use it can also constitute forgery. It's important for individuals accused of forgery to consult with an attorney to understand the specific charges and potential defenses available to them.