For years, engagement letters have been static PDF documents that clients had to print, sign, scan, and email back. This clunky process creates delays and feels outdated. It’s time to move beyond that. A modern engagement letter is an interactive digital experience that your client can sign with a single click from any device. More importantly, it can capture their payment information upfront, turning your initial agreement into an automated billing machine. This guide will walk you through the key components you need, providing a bookkeeping engagement letter template you can use to build a seamless, professional client onboarding process.