Onboarding Time

i like to see really clear business objectives expressed as problems. For example, i want to reduce the amount of time it takes new customers to unbor to our product by 50 immediately. That's going to open you up to all sorts of creativity, technical creativity, to solve that problem. So nowas y developers can start thinking abot what can we when does on boarding start? When does it finish? What metrics can i put into the features that help reduce on boarding time?