Automated User Signatures for Vouchers

I want every sales voucher leaving our system—whether it ends up printed or emailed—to carry the correct user-specific signature without anyone having to paste or sign manually. We issue both paper and digital vouchers, so the solution must handle both paths seamlessly... (Budget: ₹600 - ₹1500 INR, Jobs: API Development, C# Programming, HTML, JavaScript, PHP, Software Architecture, Software Development, User Interface / IA)