Final answer:
The process of checking and charging for a bag typically occurs at the ticket counter during the check-in process. The bag is then screened at the security checkpoint before boarding.
Step-by-step explanation:
The process of checking and charging for a bag typically varies based on the airline and its policies. However, in most cases, the bag is checked and charged for at the ticket counter during the check-in process. Once a passenger has checked in and received their boarding pass, they can proceed to the security checkpoint to be screened before boarding the plane.