Short answer. Article 171 lists eight specific acts — from forging a signature to making untruthful statements in a narration of facts, altering true dates, or making people appear to have taken part when they did not. The offender must be a public officer, employee or notary taking advantage of his position.
What the law says
Causing it to appear that persons have participated in any act or proceeding when they did not in fact so participate
Revised Penal Code, Article 171 — Falsification By Public Officer. Read the full provision →
What the law says
Issuing in an authenticated form a document purporting to be a copy of an original document when no such original exists, or including in such a copy a statement contrary to, or different from, that of the genuine original
Revised Penal Code, Article 171 — Falsification By Public Officer. Read the full provision →
Who the article binds, and the phrase that limits it
Article 171 applies to a public officer, employee or notary who, taking advantage of his position, falsifies a document. That qualifier is not decoration. It means the offender had the duty or the authority to make, prepare or intervene in the document, and used that authority to produce the falsity. A government employee who forges a private letter unconnected to his office is not covered here; a notary who notarises a deed the signatory never appeared for is squarely covered. The article extends the same penalty to an ecclesiastical minister, but only for records or documents whose falsification may affect the civil status of persons — baptismal and marriage records being the obvious examples.
The eight acts, in plain terms
The list is closed, and it is worth knowing which entry your situation fits. It covers counterfeiting or using any handwriting, signature or rubric; causing it to appear that persons have participated in any act or proceeding when they did not in fact so participate; attributing to participants statements they never made; making untruthful statements in a narration of facts; altering true dates; making an alteration or intercalation in a genuine document that changes its meaning; issuing in an authenticated form a document purporting to be a copy of an original document when no such original exists, or including in such a copy a statement contrary to, or different from, that of the genuine original; and intercalating an instrument or note in a protocol, registry or official book.
The notarised deed you never signed
By far the most common real-world complaint under this article is the deed of sale, waiver or extrajudicial settlement bearing a signature the supposed signatory did not make, or notarised as if the person appeared when they were elsewhere or already dead. That situation can engage several entries at once: the counterfeit signature, making it appear that a person participated when he did not, and an untruthful narration in the notarial certification. Because such a document enjoys a presumption of regularity and can be registered against title, the damage is immediate — property changes hands on paper.
Penalty, limits, and what to do
The penalty is prisión mayor and a fine not to exceed One million pesos (₱1,000,000). That peso figure is current because it was set by Republic Act No. 10951 (2017), which revised fines and property values throughout the Revised Penal Code. Older reproductions still print the 1930 amounts — for theft and estafa they show 12,000 and 22,000 pesos where the current figures run to millions — so check which version any source you read is giving you. Note also what this article does not do: it does not punish private individuals, who fall under a separate provision; it does not by itself cancel the false document or restore your title, which requires a civil action; and it does not reach honest errors, since the untruthful narration must be of facts the offender knew to be false. Keep certified copies, identification records and any proof of where you actually were, and consult a lawyer promptly.