To understand the requisites for the collection process under the National Internal Revenue Code of 1997 (NIRC), as amended by the Tax Reform for Acceleration and Inclusion (TRAIN) Law and Republic Act No. 11976 (Ease of Paying Taxes Act), we must meticulously review relevant provisions, procedural requirements, and the legal foundation guiding the Bureau of Internal Revenue's (BIR) authority in enforcing tax liabilities.

1. Legal Basis for Collection

The power to enforce collection of taxes due and demand payment stems from:

NIRC of 1997 (Republic Act No. 8424), particularly Sections 205-209.
TRAIN Law (R.A. No. 10963), which introduced modifications on thresholds, tax rates, and exemptions.
Ease of Paying Taxes Act (R.A. No. 11976), aimed at simplifying compliance and enhancing taxpayer services.

This framework permits the BIR to assess, collect, and enforce liabilities while ensuring taxpayers are afforded due process.

2. Requisites in the Collection Process

The collection process begins after a final assessment has been issued and becomes due and demandable. The following requisites must be fulfilled:

a. Issuance of a Final Assessment Notice (FAN) and Formal Letter of Demand

The BIR must first determine the taxpayer's liability through an audit or investigation.
The result of this assessment, known as a Final Assessment Notice (FAN), is a crucial document that specifies the amount due, with a Formal Letter of Demand for payment.
Requirements of a Valid FAN:
- Must state a specific due date for payment.
- Must be served personally or via registered mail.
- Must contain a detailed computation of the tax deficiency.
- Properly signed by the authorized BIR official.

The issuance of a FAN is essential; without it, the BIR cannot proceed with enforcement actions.

b. Due Process Requirements

Due process in tax collection entails notifying the taxpayer and allowing a reasonable opportunity to challenge the assessment.
The BIR is required to follow prescribed timelines, including the issuance of a Preliminary Assessment Notice (PAN) and the FAN.
Judicial Remedies: If the taxpayer disagrees with the FAN, they may file an administrative protest within 30 days and potentially appeal to the Court of Tax Appeals (CTA) if unresolved.

c. Issuance of a Warrant of Distraint and/or Levy

If the taxpayer fails to pay the assessed deficiency within the time specified in the FAN, the BIR may issue a Warrant of Distraint (for personal property) or Warrant of Levy (for real property).
Requirements for Warrant Issuance:
- There must be a final, executory assessment (no ongoing protest or judicial appeal).
- The taxpayer must be notified of the impending warrant.
- The BIR Commissioner or a duly authorized representative must approve the issuance.
Process of Distraint and Levy:
- Distraint involves seizing personal property or garnishing bank accounts to satisfy the tax debt.
- Levy involves selling real property to cover the liability.

Distraint and levy proceedings require strict adherence to procedural rules to avoid abuse of authority and ensure fairness.

d. Taxpayer’s Right to Redemption

In cases of levy on real property, the taxpayer has the right to redeem the property by paying the assessed tax, penalties, and interest within one year from the sale date.
This redemption right is a statutory safeguard to protect taxpayers from disproportionate enforcement actions.

e. Civil Action for Collection

In addition to administrative remedies, the BIR may file a civil action in court to recover unpaid taxes.
This step is usually taken if distraint and levy are not viable or sufficient to settle the tax debt.
Civil actions follow the rules of procedure in the Rules of Court and may be filed in the Regional Trial Court (RTC).

f. Tax Liens

Tax liens arise automatically when a taxpayer incurs a deficiency, securing the government's interest in the taxpayer's property.
For real property liens to be enforceable against third parties, the lien must be annotated in the Registry of Deeds.
Liens ensure the government’s priority over other creditors regarding the taxpayer's assets.

3. Additional Provisions under the Ease of Paying Taxes Act (R.A. No. 11976)

Simplification and Digitalization: The Ease of Paying Taxes Act introduced reforms aimed at enhancing the accessibility and efficiency of the BIR’s collection process. For instance:
- Expanded use of digital platforms for tax payments.
- Streamlined processes for small and micro taxpayers.
Taxpayer Bill of Rights: This act reinforced the rights of taxpayers, especially regarding due process and access to clear information on their liabilities and available remedies.
Electronic Invoicing and Receipting: The act mandated wider adoption of electronic invoicing, making record-keeping more accessible and audit procedures more efficient.

4. Statute of Limitations on Collection

Basic Rule: The BIR has five years from the date of assessment to collect a tax due, following the issuance of a final assessment.
Suspension of the Prescriptive Period:
- If the taxpayer is outside the Philippines.
- If the taxpayer cannot be located despite reasonable efforts.
- If the taxpayer has pending appeals or claims for refund that affect the amount due.
The statute of limitations is intended to prevent indefinite exposure to liability while ensuring prompt tax collection.

5. Judicial Remedies Available to the Taxpayer

Administrative Protest: Filed within 30 days from the issuance of the FAN.
Appeal to the CTA: If the administrative protest is denied or unresolved within the period prescribed, the taxpayer may elevate the matter to the Court of Tax Appeals.
Injunctions and Appeals in Higher Courts: In exceptional cases, injunctions may be sought to halt collection activities, though courts rarely grant these due to the state’s right to collect taxes.

6. Summary of Key Steps in Collection Process

Issuance of PAN and FAN with due process requirements.
Demand for payment within the specified period.
Issuance of distraint or levy warrants upon non-payment.
Resort to civil action if administrative remedies are inadequate.
Ensuring compliance with statutes of limitations.
Providing avenues for judicial and administrative relief to the taxpayer.

The BIR’s authority in enforcing tax collections is balanced by requirements to respect taxpayer rights, adhere to procedural due process, and observe statutory limitations on collection activities. The TRAIN Law and the Ease of Paying Taxes Act have contributed to streamlining processes and safeguarding taxpayer rights while preserving the government’s ability to collect essential revenues.