Purchase Invoice Format: Required Fields & GST Guide
5 min read
By
TranZact Solutions Team
· Published
A purchase invoice is the GST tax invoice your supplier issues, recorded on your side as a purchase. Under Rule 46 of the CGST Rules, it must show both parties' GSTINs, a unique serial number and the date. It must also list HSN codes, quantities, taxable value, the tax charged and a signature.
Get a field wrong and your input tax credit can be held up or rejected. For a manufacturer buying raw material every week, that is not a filing detail. It is money you paid and cannot claim back.
What Is a Purchase Invoice?
A purchase invoice is the tax invoice your supplier issues, seen from the buyer's side. The seller calls it a sales invoice. You record it as a purchase.
It is your proof of the purchase for accounts and GST. It also supports your input tax credit claim. Without a valid invoice that shows up in your GSTR-2B, you cannot claim the GST you paid.
Purchase Invoice Format: Required Fields Under GST
Rule 46 of the CGST Rules fixes what a tax invoice must carry. The purchase invoice you receive is that same tax invoice. Use this as your format checklist.
Invoice identity: a consecutive serial number, unique for the financial year and up to 16 characters, plus the date of issue.
Supplier details: name, address and GSTIN.
Your details: name, address and GSTIN or UIN, if you are registered.
Goods details: HSN code, description, quantity and unit for each line item.
Value and tax: taxable value, rate and amount of CGST, SGST, IGST or cess, and the total invoice value.
Supply details: place of supply with the state name for interstate supplies, and whether tax is payable on reverse charge.
Authentication: the supplier's signature or digital signature. An invoice issued electronically under the IT Act, like an e-invoice, doesn't need one.
If your supplier issues e-invoices, the invoice will also carry an IRN and a QR code. Check both are there before you record it.
Three-way check before you record an invoice
Match invoice lines to the PO
Match quantities to the GRN
Check GSTIN, HSN and tax type
Record it, then pass it to Tally
Why Purchase Invoices Slip Through in the Patchwork
In many manufacturing businesses, the PO lives in Excel, the GRN is on paper, and the invoice arrives on WhatsApp or email. Someone types it into Tally and checks it against the other two by hand.
When the floor is busy, that check gets skipped. The fault is not your team's. The tools were never connected, so a wrong rate or short quantity slips through. You find out at GST filing time, or when stock doesn't match.
Purchase invoices: patchwork vs TranZact
Tally + Excel + WhatsApp | With TranZact | |
|---|---|---|
Invoice vs PO | Checked by hand | Matched to the PO |
Paper invoice | Typed in again | Photo becomes an entry |
PO, GRN, invoice | Three separate places | One purchase flow |
Tally entry | Re-keyed by accounts | One-way sync, no double entry |
How TranZact Handles Purchase Invoices
TranZact's manufacturing AI software runs the purchase flow on one system. It goes from MRP report to indent, RFQ, PO, GRN and payment.
AI reads the supplier invoice and matches it to the PO it belongs to. Nobody has to cross-check it by hand. A photo of a paper entry becomes a system entry, so nothing gets typed twice.
When something is stuck, AI alerts the right person. Accounting stays in Tally. TranZact syncs one-way, with no double entry, and Zoho Books sync is available too.
Two limits are worth knowing. TranZact runs operations, not accounting, so your books stay with your accountant and Tally. Tally, Busy and Zoho integration, and MRP and indent planning, come with the Grow, Scale+ and Dominate plans.
See the full flow on the TranZact purchase management page.
Common Purchase Invoice Mistakes to Avoid
Watch for these five errors on every purchase invoice. Each one can hold up your input tax credit.
Wrong or missing GSTIN: one wrong digit and the invoice won't match on the GST portal. The credit gets held up or rejected.
Wrong HSN code: a misclassified item changes the tax rate. It can flag your return for scrutiny.
CGST/SGST vs IGST mix-up: intrastate tax on an interstate purchase, or the reverse. This is one of the most common purchase-side errors.
Missing signature: a paper invoice without a signature or digital signature isn't compliant, even if every other field is right. Invoices issued electronically, like e-invoices, are exempt.
Proforma recorded as a tax invoice: a proforma carries no tax liability. It cannot support an input tax credit claim.
Purchase Invoice vs Proforma Invoice vs Bill of Supply
Three documents can look alike on a supplier's letterhead. Only one of them supports an input tax credit claim.
Document | When it is issued | Charges GST? | Supports input tax credit? |
|---|---|---|---|
Purchase (tax) invoice | When goods are supplied | Yes | Yes |
Proforma invoice | Before the sale, as a quote | No | No |
Bill of supply | By composition suppliers, or for exempt goods | No | No |
If a supplier sends a proforma for a completed purchase, flag it before you record it. Ask for the tax invoice instead.
What to Check Before You Choose Software for Purchase Invoices
If invoice checks eat your accounts team's week, the software should take that load off. Ask these questions in any demo.
Does the supplier invoice match to the PO without someone checking line by line?
Can it read a paper or photographed invoice, so nobody retypes it?
Do the PO, GRN and invoice sit in one flow, not three tools?
Does Tally stay as it is, with no double entry?
Does it generate the e-invoice and e-way bill on your own sales?
How long does it take to go live, and does it need a consultant?
TranZact generates the e-way bill from the GST invoice, with e-invoice (IRN) in the same flow, on all plans. It goes live in 2–3 weeks, with no consultants and no IT team.
It is built on 7 years of learning from 10,000+ manufacturers.
See It on Your Own Invoices
Bring a few real supplier invoices to the demo. We'll show you how TranZact matches them to your POs and passes clean entries into Tally.
