Step 1
Send vendor intake form
Collect basic vendor information: company name, contact details, payment preferences, and services provided.
For AP Teams
Vendor Onboarding: A Complete Guide
A streamlined vendor onboarding process saves time, ensures compliance, and sets up your accounts payable team for success. Here's how to do it right.
The Vendor Onboarding Process
Step 2
Request W-9
Send a W-9 request to get the vendor's tax information. This is required before any payments can be made.
Step 3
Verify tax information
Run TIN matching to verify the vendor's name and tax ID match IRS records before adding them to your system.
Step 4
Set up in accounting system
Create the vendor record in your accounting software with verified information for accurate 1099 reporting.
Step 5
Approve and notify
Complete any internal approvals and notify the vendor they're set up and ready for invoicing.
Why W-9 Collection is Critical
The W-9 is the foundation of vendor onboarding for several reasons:
- Tax compliance: You need the vendor's TIN to file accurate 1099s at year-end
- Backup withholding: Without a valid W-9, you must withhold 24% of payments
- Audit protection: W-9s on file demonstrate due diligence during audits
- Accurate records: The legal name and address on the W-9 ensure correct payment records
When to Collect the W-9
Best practice: Before the first payment. Many organizations won't process a vendor's first invoice until a W-9 is on file. This ensures you never have to chase vendors for tax information at year-end.
Some teams collect W-9s even earlier — as part of the initial vendor application or contract signing process. The earlier you collect it, the fewer problems you'll have later.
Common Challenges & Solutions
Vendors don't respond to W-9 requests
Solution: Use digital W-9 collection with automatic reminders. Make it easy with a simple link instead of PDF attachments.
W-9s have errors or missing information
Solution: Use an online form that validates fields and requires all necessary information before submission.
No visibility into onboarding status
Solution: Track all vendor requests in a dashboard with clear status indicators (pending, completed, etc.).
Year-end scramble for missing W-9s
Solution: Collect W-9s before the first payment, not at year-end. Make it a non-negotiable part of onboarding.
Vendor Onboarding Checklist
- Vendor name and DBA (if applicable)
- Primary contact name, email, and phone
- Remittance address
- W-9 form with valid TIN
- TIN matching verification
- Payment terms (Net 30, etc.)
- Payment method preference (check, ACH, etc.)
- Banking information (for ACH payments)
- Insurance certificates (if required)
- Signed vendor agreement or contract
- Internal approval signatures
Automating Vendor Onboarding
Manual vendor onboarding is slow, error-prone, and frustrating for both AP teams and vendors. Modern organizations automate key parts of the process:
- Digital W-9 collection: Send a link instead of email attachments; get notified when it's complete
- Automatic reminders: Stop manually following up on missing documents
- Centralized tracking: See all pending and completed vendor setups in one place
- Integration with accounting: Sync verified vendor data directly to your accounting system
Streamline your vendor onboarding
Collect W-9s digitally with automatic reminders and status tracking.