Each charger ‘should’ have its own socket outlet and be on its own circuit.
As many consumer incoming mains are in the 35A to 50A range, even one added 16A charging socket-outlet can cause an overload. So, when an EV charging point is added, the electrician should do a maximum demand assessment. This can mean a consumer mains upgrade.
It may also go further, requiring upgrading of the distributor lead-in from the street, especially if there is more than one EV and they are on separate socket outlets, as in AS/NZS 3000 Appendix P. Switchboard upgrading or replacement may result, and additional AS/NZS 3000 requirements may apply.