Sending an invoice seems straightforward until you actually sit down to do it. Which fields are mandatory? Do you need GST? What should your payment terms say? How do you follow up without sounding desperate?
This guide answers all of it — in plain language, for Indian freelancers and small business owners.
What Is an Invoice and Why It Matters
An invoice is a legally recognized commercial document that requests payment for goods or services delivered. In India, a proper invoice also serves as the basis for:
- GST input tax credit (for your GST-registered clients)
- Proof of income for ITR filing
- Legal recourse if a client refuses to pay
- Professional credibility — clients trust vendors who send clean, complete invoices
A badly formatted invoice — missing PAN, wrong GSTIN, no invoice number — can get rejected by a client's accounts team, delaying your payment by weeks.
The Two Types of Invoices in India
1. GST Tax Invoice
Required if you are GST registered and the supply is taxable. Must include your GSTIN, HSN/SAC code, and breakup of CGST + SGST or IGST.
2. Bill of Supply / Simple Invoice
Used if:
- You are not registered under GST (annual turnover below ₹20 lakh for services, ₹40 lakh for goods)
- The supply is GST-exempt
- You are registered but billing an exempt supply
For most freelancers earning under ₹20 lakh/year, a simple invoice without GST is perfectly legal.
What Goes on an Indian Invoice — Field by Field
Mandatory Fields (All Invoices)
| Field | Description |
|---|---|
| Invoice Number | Sequential, unique (e.g., INV-2026-001) |
| Invoice Date | Date of issue |
| Your Name / Business Name | As per PAN or GST registration |
| Your Address | Full address including state |
| Client Name & Address | Full legal name, billing address |
| Description of Services/Goods | Clear, specific — not just "services" |
| Quantity & Rate | Itemized breakdown |
| Total Amount | Before and after tax |
| Payment Terms | Due date, accepted payment methods |
| Bank Details | Account number, IFSC, bank name |
Additional Fields for GST Invoices
| Field | Description |
|---|---|
| Your GSTIN | 15-digit GST Identification Number |
| Client's GSTIN | If client is GST registered |
| Place of Supply | State where supply is made |
| HSN Code (goods) or SAC Code (services) | e.g., SAC 9983 for IT/software services |
| Tax Rate & Amount | CGST + SGST (intrastate) or IGST (interstate) |
| Reverse Charge | Yes/No — usually "No" for most freelancers |
Step-by-Step: Creating Your First Invoice
Step 1 — Set Up Your Invoice Template
Either use software (more on this below) or set up a reusable template. Include your logo, brand colors, and pre-filled contact details so you're not re-entering them every time.
Step 2 — Assign an Invoice Number
Use a consistent numbering system. Options:
- Sequential: INV-001, INV-002
- Date-based: INV-20260511-001
- Client-based: ACME-2026-01
Never reuse invoice numbers — it's a red flag for auditors and confuses your own records.
Step 3 — Add Client Details Carefully
Double-check:
- Correct legal business name (not just the brand name)
- Complete billing address with PIN code
- GSTIN if they're GST registered (they'll ask you for input credit)
Step 4 — Describe Your Work Clearly
Vague descriptions like "consulting" or "work done in April" get flagged by accounts payable teams. Instead write:
Website redesign — 3 pages (Home, About, Services) — as per scope dated 15 March 2026
Or for retainers:
Social media management — April 2026 — 20 posts + story content as per agreement
Step 5 — Calculate GST Correctly
If you're GST registered:
- Intrastate (both you and client in same state): Add 9% CGST + 9% SGST
- Interstate (different states): Add 18% IGST
- Exports: Zero-rated (0% GST, but you must file LUT)
Most freelance services fall under 18% GST.
Example:
Service Fee: ₹50,000
CGST @ 9%: ₹4,500
SGST @ 9%: ₹4,500
Total Payable: ₹59,000
Step 6 — Set Clear Payment Terms
Don't just write "payment due soon." Specify:
- Due date: "Payment due within 15 days of invoice date — by 26 May 2026"
- Late fee: "1.5% per month on overdue amounts"
- Accepted methods: NEFT, RTGS, UPI (include UPI ID or QR)
Step 7 — Add Your Bank Details
Indian clients pay almost exclusively via bank transfer or UPI. Always include:
- Account holder name
- Account number
- IFSC code
- Bank name and branch
- UPI ID (optional but helpful for faster payments)
Step 8 — Send and Track
Email the invoice as a PDF. In the email subject line, include the invoice number and amount:
Subject: Invoice INV-2026-047 — ₹59,000 — [Your Name/Company]
Use invoicing software that shows you when the client opens the PDF.
GST Invoice vs Non-GST Invoice: Quick Comparison
| Scenario | Invoice Type | GST Charged |
|---|---|---|
| Turnover < ₹20L (services), not registered | Simple Invoice | No |
| Turnover > ₹20L or voluntarily registered | Tax Invoice | Yes (18% for most services) |
| Exporting services | Tax Invoice (LUT filed) | 0% (Zero-rated) |
| Selling exempted goods/services | Bill of Supply | No |
Payment Terms That Actually Work
The most common mistake Indian freelancers make: writing "due on receipt" and then following up for 60 days.
Here's what works:
50% Advance + 50% on Delivery
Best for new clients and project-based work. Protects you from non-payment and forces commitment upfront.
Net 15
Payment within 15 days. Reasonable for established clients. Add a 1.5% monthly late fee clause.
Milestone-Based
For long projects: 30% at start, 40% at midpoint, 30% at delivery. Aligns cash flow with progress.
Subscription/Retainer
Bill on a fixed date each month (e.g., 1st of month). Auto-reminders from invoicing software handle this well.
Following Up on Unpaid Invoices
Don't feel awkward — it's your money. Here's a simple follow-up timeline:
| Day | Action |
|---|---|
| Invoice sent | Confirmation email: "Please find Invoice #047 attached" |
| Day 3 | Soft check: "Did the invoice arrive okay?" |
| Day 15 (due date) | Polite reminder with invoice attached |
| Day 20 | Firm reminder with late fee notice |
| Day 30 | Final notice — mention legal action if needed |
| Day 45+ | Consider MSME Samadhaan portal or legal notice |
Pro tip: Clients who owe money often ghost emails. A WhatsApp message with the invoice PDF attached often gets a faster response than email.
Tools to Create Professional Invoices Instantly
You don't need to design invoices in Word or struggle with Excel formulas. InvoiceAI lets you create GST-compliant invoices in under 2 minutes — it auto-fills your GSTIN, calculates GST, assigns invoice numbers, and sends professional PDFs.
Use the free GST invoice generator to create your first invoice right now — no sign-up required.
Other options include Zoho Invoice (good but complex for simple use cases), Wave (free but US-focused), and basic Excel templates (error-prone and time-consuming).
Common Invoicing Mistakes to Avoid
- Wrong or missing GSTIN — Your invoice will be rejected for input credit
- No invoice number — Hard to track and looks unprofessional
- Vague service description — Causes delays in accounts approval
- Missing bank details — Client can't pay even if they want to
- No due date — "Payment due on receipt" is legally ambiguous
- Not keeping copies — You need 6 years of records under GST law
Legal Protections for Freelancers in India
MSME Act (if you're registered as MSME)
Under the MSME Development Act, buyers must pay within 45 days of accepting goods/services. If they delay, they owe you compound interest at 3x the RBI bank rate — currently around 15-18% annually.
Register as an MSME at udyamregistration.gov.in — it's free and takes 10 minutes.
Income Tax Act
Keep all invoices for a minimum of 6 years for tax audit purposes. Digital copies (PDF) are accepted.
Frequently Asked Questions
Q: Can I invoice a client without GST registration?
Yes. If your annual turnover is below ₹20 lakh (services) or ₹40 lakh (goods), you are not required to register for GST. You can issue a simple invoice without charging GST.
Q: Is a hand-written invoice legal in India?
Technically yes, but it's not practical. Digital invoices are accepted everywhere and are easier to track, store, and send.
Q: Does every invoice need a PAN number?
PAN is not mandatory on every invoice, but it's required for transactions above ₹50,000 per year with the same party under Form 60/61 rules. Including it proactively builds trust.
Q: What SAC code should freelancers use?
Most freelance services (design, writing, development, consulting) fall under SAC 9983 (other professional, technical and business services) or SAC 9984 (telecommunications services for IT). Check the GST portal's HSN/SAC finder if you're unsure.
Q: Can I charge a late payment fee?
Yes. If it's mentioned in your contract or invoice terms, you can charge a late fee. The standard practice is 1.5% to 2% per month on the overdue amount.
Q: My client wants a "self-billing" arrangement. Is that legal in India?
Yes, under GST rules, a recipient can issue an invoice on behalf of the supplier in specific cases (mostly reverse charge scenarios). This is uncommon for typical freelance work. Consult a CA if a client proposes this.