If the department or position is wrong
Go to Employee > Employees.
Open the three-dot menu to the right of the employee and click Edit Personal Information.
Use the edit button under Position to remove the old value and set the correct one.
If the branch is wrong
Open the three-dot menu to the right of the employee and go to Assign.
Choose Branch Assignment and assign the employee to the correct branch.
If the position you need is not in the list
The position has to be added to the organization first. In Organization > Organization Management, use the + button above the Position heading to add it, then assign it to the employee.