If you have a card number on your license you will find it here:

Back of card, right-hand side, under enlarged number/on top of reverse strip.

Can I access my Victorian Driver Licence card number online?

All account holders can see their card number (and their licence/permit number) in the Licences and Learner Permits section of their myVicRoads account. The card number can be accessed once you have activated two-step verification on your myVicRoads account.

Read for additional information: https://www.vicroads.vic.gov.au/licences/licence-and-permit-types/cards-and-card-numbers