I'm here to ensure you can make an employee inactive in your QuickBooks Online account. This way, you'll be able keep your employee list up to date.
Go to the Workers menu.
Locate and click the name of the employee.
Select Pencil icon next to Employment.
Choose Not On Payroll in the Status field.
You can view the inactive employee by selecting the Inactive Employees option beside the Find an employee field in the Employees window.
You can remove or re-add an employee by changing his/her employment status. Kindly refer to Change employee's employment status section in this article for the detailed steps: Delete or terminate an employee. It also explains about deleting an employee in the system.
Please let me know if you have other concerns. I'm just around to help.