Summary
Konfir may ask for your National Insurance (NI) number during the payroll step to help match your record precisely.
Use the official government tool at gov.uk/find-national-insurance-number. You'll need to sign in to your HMRC account - your NI number will be displayed straight away.
Other places it appears
Payslips - usually printed near the top
P60 - your annual income and tax summary
Letters from HMRC - any correspondence will include it
Your HMRC personal tax account at tax.service.gov.uk
If you don't have an NI number yet
If you've recently moved to the UK or have never worked here, you may not yet have one. Skip the payroll step and use your bank account or HMRC instead - they can confirm your employment history without it.