Onboarding and Offboarding

In cybersecurity we don't spend as much time as we probably should in the area of onboarding and offboarding.  Initiated by the HR department or in smaller companies perhaps handled by the company owner to bring in new employees and then of course when an employee exits the company what does that process look like.  Is this process documented and is the workflow the same for onboarding as it is offboarding? This and many other questions associated with people and their role within a company as they are hired and what happens when they leave.  Thanks to Joshua Smith of Reliaquest for walking me through his recent journey of leaving one company to take a new role with another.