Yes, it is definitely possible to appoint or remove officeholders and directors after company registration, however you must directly notify ASIC of any changes within 28 days of the appointment or removal.
There is a specific process that you must follow to lodge these updates with ASIC. First, you must use the company’s corporate key (an 8-digit number generated by ASIC within 10 days of company registration and posted to the company’s registered office address) to create an ASIC Officeholders account. Please follow the link to set up this account: http://asic.gov.au/online-services/register-for-online-access/company-officeholders/
From within that account you will need to submit an electronic Form 484 to appoint/remove officeholders and shareholders.
For detailed assistance, it's recommended to contact Namecorp’s Support and Compliance Team either by phone on 1300 006 263 or via email at support@namecorp.com.au, they’re always there to help you through every aspect of your business journey.