How to Document Sales and Expenses for Easy GST/QST Filing — Montreal CPA Firm

Accurate documentation is the foundation of clean GST/QST filings. Whether you operate a consulting business, retail shop, construction company, e-commerce store, or professional practice, your ability to properly document sales and expenses determines whether your returns are accepted, whether your refunds are released quickly, and whether you survive a Revenue Québec or CRA review. Most businesses do not get audited because they did something wrong — they get audited because their documents are incomplete, inconsistent, or poorly organized. This guide explains how to document every transaction correctly using the same audit-proof system Mackisen CPA Montreal builds for its clients.

Why This Matters
GST/QST compliance is based on evidence. Revenue Québec and CRA expect all claimed ITCs/ITRs, all GST/QST collected, and every number in your return to be fully supported by documents. If your documentation is incomplete or mismatched, the government can deny credits, freeze refunds, issue reassessments, or expand the audit to previous years. With proper documentation, your filings sail through the system with no delays.

Legal and Regulatory Framework
Documentation rules fall under both the Excise Tax Act (GST) and the Tax Administration Act (QST).
Businesses must keep all supporting documents for six years.
Hickman Motors (1997, SCC) confirms the taxpayer bears the burden of proof.
Canderel (1998, SCC) requires financial reporting to reflect commercial reality.
Lac d’Amiante (2001, SCC) reinforces that RQ can reassess when documentation is incomplete.

A business files a $18,000 QST refund. Days later, a Request for Information arrives. Revenue Québec asks for all invoices, merchant reports, proofs of payment, contracts, and reconciliations. The business discovers it never downloaded Shopify invoices, some suppliers didn’t list their QST numbers, and half the deposits don’t match the reported sales. RQ denies $18,000 of ITRs and flags the business for review on every future return. All because documentation was not maintained properly.

Learning Section: What Proper Documentation Looks Like
To support GST/QST filings, every transaction must have two components:
A valid document
Proof of payment
A valid document includes:
Tax invoice
Supplier’s legal name
Supplier’s GST/QST number
Your business name
Description of goods/services
GST and QST shown separately
Date and invoice number
Proof of payment includes:
Bank statement
Interac e-transfer confirmation
Credit card statement
PayPal/Stripe receipt
For expenses over $30 (often even lower), proper invoices are mandatory.

SEO Learning: Primary and Secondary Keywords
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How to Document Sales Correctly
For every sale, keep:
Customer invoices showing GST/QST
POS or e-commerce order summaries
Stripe/PayPal/Shopify payout reports
Bank deposits matching sales
Contracts or agreements
Export documentation for zero-rated sales
If your sales are not documented, GST/QST collected cannot be properly reconciled.

How to Document Expenses Correctly
For every expense:
Collect the supplier invoice
Verify GST/QST numbers
Confirm the tax amount
Attach proof of payment
Code it correctly in your accounting software
Record any credits or refunds
Expenses missing invoices or payment proof cannot be claimed as ITCs/ITRs.

Documentation Section: Six-Year Storage Requirement
Revenue Québec and CRA require you to keep:
Invoices
Receipts
Bank statements
Merchant processor summaries
Contracts
Reconciliations
Proof of payment
Filing confirmations
Export logs
Software system reports
Keep everything for six full years after the last year the document relates to.

Common Documentation Mistakes
Using credit card slips as invoices
Missing supplier tax numbers
Not matching deposits to sales
Failing to download invoices from online stores
Not keeping proof of payment
Not documenting zero-rated exports
Incorrect tax coding in software
Deleting emails with attached receipts
Not storing documents in one organized system
Not reconciling merchant processor payouts
These mistakes cause most refund delays and audits.

Winning With Revenue Québec and Canada
Mackisen builds a complete documentation ecosystem for your business. We organize your sales and expenses by category, set up digital folders, match deposits to sales, match payments to invoices, and reconcile all GST/QST accounts. When CRA or RQ requests documents, we produce a complete audit binder — indexed, labeled, and compliant. Our system ensures your refunds are released quickly, your filings are accepted, and your audits are closed with minimal questions.

Mackisen Service Hub
We provide:
Sales documentation systems
Expense documentation systems
GST/QST audit-proof folders
Reconciliation systems for Stripe, PayPal, Square, Shopify
Full digital filing systems
Support with Requests for Information
Corrected filings and amendments
Every system is designed to protect your business from documentation-related reassessments.

Why Mackisen
With over 35 years of CPA and audit experience, Mackisen CPA Montreal ensures your documentation is complete, organized, compliant, and fully defensible. We help businesses eliminate refund delays, avoid audits, and protect their GST/QST filings with strong, reliable evidence.