In the Philippine legal system, a Petition is a formal written application made to a court or a quasi-judicial body, seeking a specific judicial action, relief, or remedy. Unlike a typical "Complaint" which initiates a civil action, a petition is often the vehicle for special civil actions (like Certiorari or Mandamus), special proceedings (like Adoption or Habeas Corpus), or appeals via Petition for Review.

Adherence to the prescribed format and requirements is not merely a matter of style; it is a jurisdictional and procedural necessity under the Rules of Court and relevant circulars issued by the Supreme Court.

I. The Formal Parts of a Petition

Every petition must generally follow this structural hierarchy:

1. The Caption

Located at the top of the first page, the caption must include:

The Name of the Court: (e.g., "Republic of the Philippines, Regional Trial Court, Branch 10, Manila").
The Title of the Case: This includes the names of the parties. The initiating party is the Petitioner, and the responding party is the Respondent.
The Docket Number: Usually left blank if it is the initiating pleading, to be filled by the Clerk of Court.
The Designation: A clear title of the pleading (e.g., "PETITION FOR HABEAS CORPUS").

2. The Body

The body of the petition is divided into several essential sub-sections:

Parties: A brief description of the petitioner and respondent, including their legal capacities and addresses for service of processes.
Statement of Matters Involved: A concise summary of the legal issues.
Statement of Facts: A clear, chronological, and concise recital of the ultimate facts on which the petitioner relies.
Issues: The specific legal questions the court is asked to resolve.
Arguments/Discussion: The legal basis, citing statutes, administrative orders, or Supreme Court jurisprudence.
Relief / Prayer: A specific statement of what the petitioner wants the court to do (e.g., "Wherefore, it is respectfully prayed that...").

3. The Signature and Address

The petition must be signed by the party or the counsel representing them. This signature constitutes a certification that the signer has read the pleading and that there are good grounds to support it.

II. Mandatory Attachments and Certifications

A petition that lacks these specific additions is often subject to immediate dismissal:

1. Verification

A petition must be verified. This is a statement under oath by the petitioner (not the lawyer) confirming that:

They have read the petition.
The allegations therein are true and correct based on their personal knowledge or authentic records.

2. Certification Against Forum Shopping

The petitioner must certify under oath that:

They have not commenced any other action involving the same issues in any other court or tribunal.
To the best of their knowledge, no such action is pending.
If they learn of such an action, they will report it to the court within five days.

Note: Failure to comply with the Certification Against Forum Shopping is generally not curable by amendment and is cause for dismissal with prejudice.

3. Explanation of Service

Under Rule 13 of the Rules of Court, if the petition is filed or served via registered mail or other means instead of personal service, a written explanation must be included as to why personal service was not practiced.

4. Proof of Payment

Payment of the prescribed docket and other lawful fees is mandatory. The court acquires jurisdiction over the case only upon the full payment of these fees.

III. Technical Specifications (Efficient Use of Paper Rule)

Pursuant to Administrative Matter No. 11-9-4-SC, all pleadings filed in Philippine courts must follow the Efficient Use of Paper Rule:

Paper Size: 8.5 x 13 inches (Long Bond/Legal Size).
Margins: Left (1.5 inches); Top (1.2 inches); Right (1.0 inch); Bottom (1.0 inch).
Font and Size: 14-point font (usually Arial or Times New Roman).
Spacing: One-and-a-half (1.5) space.
Copies: The number of copies depends on the court (e.g., an original and two copies for Regional Trial Courts; more for the Court of Appeals or Supreme Court).

IV. Specialized Requirements for Specific Petitions

Certified True Copies: For Petitions for Certiorari (Rule 65) or Petitions for Review, the petitioner must attach clearly legible duplicate originals or certified true copies of the judgment or order being assailed.
Affidavits: Special proceedings often require supporting affidavits from witnesses to be attached to the initial petition.
MCLE Compliance: Lawyers signing the petition must indicate their Minimum Continuing Legal Education (MCLE) certificate number and the date of issue to prove they are updated with their legal studies.