Source documents and voucher types: the paper trail behind every entry in your books

Every rupee in your accounts should point back to a document: an invoice, a bank line, a receipt or a signed cash voucher. When your CA asks what a ₹48,000 debit was, when your bank wants to see the sales behind your turnover, or when a GST officer asks for the invoice behind an input tax credit, your books are only as good as the paper trail behind them. This lesson shows you which documents to collect, which voucher each one becomes, and how to number and file them so nothing is lost between the shop counter and the ledger.

What you need to know

Source document versus voucher. A source document is the evidence created when a transaction happens: the tax invoice you issue, a supplier's bill, a bank statement line, a cash memo, a delivery challan, a salary sheet. A voucher is the accounting record you create from that evidence in TallyPrime, Zoho Books, Busy or a handwritten register. It names the accounts affected, the amounts and a short narration. One document usually produces one voucher, but a single voucher can rest on several documents — a payment to a supplier is backed by their bill and by your bank debit.

The eight voucher types. Almost every transaction in a small Indian business fits one of these:

• Sales — goods or services you supply, for cash or on credit. Evidence: your tax invoice or bill of supply.
• Purchase — goods bought for resale or production, and often services, on credit or for cash. Evidence: the supplier's invoice.
• Receipt — money coming in from anyone: a customer, a lender, the owner putting in capital. Evidence: bank credit, UPI record, your receipt copy.
• Payment — money going out: supplier, rent, salary, electricity, tax. Evidence: bank debit, cheque counterfoil, or a cash voucher signed by the person paid.
• Contra — money moving between your own cash and bank accounts: cash deposited, cash withdrawn, a transfer from your current account to your overdraft account. No outside party is involved.
• Journal — adjustments with no cash movement: depreciation, expenses due but unpaid, corrections, transfers between ledgers.
• Credit note — you reduce what a customer owes you after a return, a rate correction or a discount given after the sale.
• Debit note — you record a reduction in what you owe a supplier after a purchase return, a shortage or a rate difference.

A quick test: if an outsider is involved and money moves, it is a receipt or payment; if only your own cash and bank accounts are involved, it is contra; if no money moves, it is a sale, purchase, note or journal.

What a usable bill shows. Supplier name and address, GSTIN if registered, invoice number and date, your business name (not your personal name), description, quantity, rate, taxable value, tax split and total. Input tax credit generally depends on holding a valid tax invoice that shows your GSTIN correctly and on the supplier reporting that invoice — confirm the current conditions on the GST portal or with your CA before you rely on a credit.

Internal vouchers for expenses without bills. Tea for staff, local auto fares, a roadside repair — these rarely come with a proper bill. Create an internal cash voucher: serial number, date, amount, purpose, name and signature of the person receiving the money, and approval by you or a manager. It is weaker evidence than a supplier bill, so keep such expenses small, occasional and approved.

Numbering series. Sales invoices must carry a consecutive serial number that is unique within the financial year, and the GST rules set conditions on its format and length, which you should confirm on the GST portal. Use a prefix per branch or document type, such as JPR/26-27/0001 for Jaipur invoices and JPR-CN/26-27/001 for credit notes. Never delete a cancelled invoice: keep it, mark it cancelled and note why. Gaps in a series are the first thing an auditor looks for.

Filing that survives a staff change. A common rule of thumb is one folder per month, with sub-folders per voucher type and documents in voucher-number order. Once a bill is entered, write the voucher number on it (for example "P-0042 entered") and name its scan the same way. If your software lets you attach a file to a transaction, attach the scan to the voucher itself.

How long to keep them. GST law, income-tax law and company law each require books and supporting documents to be kept for a number of years, and the periods are not identical. Ask your CA for the longest period that applies to your entity and keep both paper and scans at least that long.

This lesson is education on bookkeeping practice; for the requirements that apply to your business, consult a qualified Chartered Accountant.

Step-by-step method

1. List every way money or goods move through your business in a normal month: counter sales, credit sales, online orders, supplier purchases, rent, salaries, loans, owner withdrawals, cash deposits.
2. Against each flow, write the source document you should receive or create, and the voucher type it becomes.
3. Mark the flows that currently have no document at all. For each, decide the fix: ask the supplier for a bill, issue a receipt, or use an internal cash voucher.
4. Set a numbering series for every document you issue — sales invoices, credit notes, receipts, internal cash vouchers — with a branch or type prefix and the financial year.
5. Create an internal cash voucher format and keep a numbered pad at the cash counter.
6. Decide who collects documents and by when: for example, counter staff hand over the day's bills every evening and the owner forwards e-mailed bills every Saturday.
7. Enter each document into your software, write the voucher number on it, and file it in that month's folder.
8. At month-end, check each series for gaps and compare the number of documents in each folder with the number of vouchers in the software.

Common mistakes

• Entering a supplier payment straight from the bank statement without the supplier's bill, so the expense has no evidence and the input GST is lost.
• Recording a cash deposit into your own bank account as a receipt from a customer, which inflates sales on paper.
• Deleting a cancelled invoice to "clean up", leaving a gap in the series that an auditor or GST officer will question.
• Accepting bills made out in the owner's personal name for business purchases, weakening both the expense claim and the credit.
• Using internal cash vouchers for large or regular expenses that should carry a proper supplier bill.

Ask the AI Business Tutor

• "I run a [type of business] in [city] with [number] staff. Money comes in through [channels, e.g. counter cash, UPI, credit customers] and goes out on [main expenses]. List each transaction flow, the source document I should hold for it and the voucher type it becomes in [TallyPrime / Zoho Books / manual books], and flag any flow where I currently have no document: [describe the gaps you know of]."