TL;DR: Employee onboarding is a 90-day to 1-year process that helps new hires succeed through preboarding, orientation, training, and ongoing support. Good onboarding improves retention, productivity, and engagement. It needs clear phases, defined roles for HR and managers, regular check-ins, and metrics to track progress.Your first impression as an employer happens during onboarding. Get it right, and new hires become productive team members who stick around. Get it wrong, and you’re back to recruiting within months.