You can mark all the incomplete onboarding checklist items as complete for an employee before you process them as a leaver, follow the steps below.
On Portal go to People Management.
Find the employee in question via Employees or Onboarding on the Command Centre widget by clicking on VIEW for one of these options.
if using the Employee Search screen (Employees) find the employee in question, click View next to their record and click the Onboarding tab.
if using the Onboarding Progress screen (Onboarding) find the employee in question and click View next to their record.
The list of the incomplete checklist items will appear under Tasks Outstanding, click Complete All to mark them as complete.