At the top of the drawer you can find a dropdown menu with available statuses for a cargo, which will open by clicking on the current status:
The cargo status is a helper for you to understand where in the process you are. All statuses apart from 'Clean Fix' are the same in the sense that they do not change the functionality of the system. When you set the cargo status to 'Clean Fix', the Cargo Quantity in the Cargo drawer changes to be B/L Quantity. Meaning, when changing the Cargo Quantity on a 'Clean Fix"'cargo, it only changes the B/L Quantity, and not the Booked Quantity.
For a cargo, you can change the status to 'Loaded' only from the status 'Clean Fix'. You are also able to change back to 'Clean Fix' from the status 'Loaded'. The same Deadfreight/Overage, Booked Quantity, etc. calculations will happen when in these two statuses. Likely, this status will be used to mark the last transition of a cargo.
All cargoes on a voyage will have their status changed to 'Clean Fix' when the voyage is changed to 'Nominated' status. The only exception to this is if the cargo already has status 'Loaded'.