Invoices, quotations, lab reports, admit cards, policy copies, warranty cards: a lot of business paperwork in India now travels as a PDF on WhatsApp. Sending one from a staff member’s phone is easy. Sending hundreds a day from your billing or ERP system, on one official number, with a record of what went to whom, needs the WhatsApp Business API. This guide explains the two ways to send a PDF on WhatsApp Business, how a document header template works, the file limits to plan around, and the mistakes that make documents fail.
Two ways to send a document
The WhatsApp Business API treats documents differently depending on whether the customer has written to you in the last 24 hours.
| Situation | How the PDF goes out | Example |
|---|---|---|
| Customer messaged you in the last 24 hours | As a normal document message, with an optional caption | “Please send my last invoice again” |
| No recent message from the customer | Inside an approved template with a document header | Invoice sent automatically when a bill is raised |
Inside the 24-hour window your team or your system can send any file. Outside it, WhatsApp only allows approved templates, so a document you send on your own initiative has to ride on a template. For a refresher on categories and the window, see WhatsApp template messages.
Sending a PDF from the chat inbox
On the BitVoice Social Media Platform, agents answer WhatsApp, Instagram and web chat from one shared inbox. To send a document in an open conversation:
- Open the chat and click the paper-clip.
- Pick the file. Images, videos, audio, PDF, DOC and DOCX are allowed, up to 16 MB on WhatsApp.
- Watch the upload bar, then send.
The customer sees the file name and can open it on their phone. Documents that customers send to you, such as a prescription or a signed form, show in the same chat with Download and Preview buttons, so nobody has to forward files from personal phones.
Sending a PDF automatically from your system
Most document traffic should not depend on someone clicking. Your billing software, ERP or CRM can send PDFs through the HTTP API.
Inside the 24-hour window: send-media
The send-media endpoint takes the phone number, the type (document), the file itself (up to 16 MB) and an optional caption such as “Your invoice for October”. It suits replies to a customer who has just asked for something.
Outside the window: a template with a document header
For invoices, statements and reports that you send first, create a Utility template with a Document header. The body carries the variables, for example:
“Hi {{1}}, your invoice {{2}} for {{3}} is attached. Reply here if you have any questions.”
When you submit the template, you upload a sample PDF so Meta can review it. When you send the real message, you pass the actual PDF as a public URL in the header parameter, and the customer’s name, invoice number and amount in the body. The send-template endpoint does this in one call, and every message also appears in the chat inbox so your team can see what went out. For the wider integration picture, read WhatsApp API integration with CRM.
File limits and formats
| Where | What is allowed | Size limit |
|---|---|---|
| Chat attachment (WhatsApp) | Images, video, audio, PDF, DOC, DOCX | 16 MB |
| API send-media | Image, video, document or audio | 16 MB |
| Media library upload | Images and documents (PDF, Word, Excel, PowerPoint, RTF, TXT, CSV) | 16 MB |
| Template document header sample (for Meta review) | 100 MB |
Keep real documents well under these limits. A one-page invoice should be a few hundred KB. Large scanned PDFs are slow to download on mobile data and often go unopened.
The public URL rule
The most common reason a document template fails is the link. The header file must be reachable on the internet without a login. A file on someone’s computer, a Google Drive sharing page or a portal link that asks for a password will fail.
Practical options:
- Host generated PDFs on your own server or cloud storage under an unguessable path, and expire them after a period you choose.
- Upload a fixed file, such as a brochure or price list, to the media library and use Copy URL to get a link for the template header.
Because the link is public, treat it carefully. Use long random file names rather than “invoice-1001.pdf”, so nobody can guess the next customer’s document, and remove old files when they are no longer needed.
Sending documents to many customers
Month-end statements or fee receipts can go out as a campaign. A campaign sends one approved template to a list, and a document header can be the same file for everyone or mapped from a column so each person gets their own PDF. Campaigns send in paced batches to protect your number’s quality rating. Only send to customers who agreed to receive these messages; WhatsApp opt-in and quality rating explains why that matters.
Good practice for business documents on WhatsApp
- Say what the file is in the message. “Invoice INV-2291, due by 10 November” helps the customer and shows up in chat search.
- Name files clearly. The customer sees the file name before opening it.
- Do not send sensitive documents to unverified numbers. Check the number on record before sending lab reports, policy copies or bank statements.
- Keep one official number. Documents from a known business number are trusted; files from a random staff phone are not.
- Let customers reply. A question about an invoice is easier to answer in the same chat than on a call.
Want invoices, reports or receipts to reach customers on WhatsApp straight from your system? Talk to BitVoice.
FAQs
Can I send a PDF on WhatsApp Business API without a template?
Only if the customer has messaged you in the last 24 hours. Outside that window the PDF must be sent as the document header of an approved template.
What is the maximum PDF size I can send?
On the BitVoice Social Media Platform, chat attachments and API media messages go up to 16 MB. Keep business documents much smaller so they download quickly on mobile data.
Why did my document template fail to send?
The usual cause is a header link that is not public, such as a Google Drive page or a link that needs a login. The PDF must open directly from a public URL.
Can each customer get a different PDF in one campaign?
Yes. A campaign can use the same file for everyone or map a column in your contact list so each person receives their own document.
