To pay for travel on CityLink or any Melbourne toll road you need to buy a pass or open an account.
If you've already travelled on CityLink, you can pay for your previous travel by:
Alternatively, you can wait for a toll invoice to arrive in the mail. Toll invoices are sent to the vehicle's registered owner and include a toll invoice admin fee as well as the cost of your CityLink travel.
It may take up to 4 weeks for a toll invoice be issued.