In case when capital gain is fully exempt, it may not be included in tax form. User can remove amount and fill only exemption code. Below is the sample image on how you will fill-up the CGT Schedule:

ATO related link-  https://www.ato.gov.au/individuals-and-families/your-tax-return/instructions-to-complete-your-tax-return/mytax-instructions/2024/income/australian-income-or-losses-from-investments-or-property/capital-gains#CGTexemptionrolloveroradditionaldiscount


NOTE: Alternatively, you can add additional information (as text only) to ATO via the "Additional Information for the ATO (via the "Individual" tab for the ITR form). Related guide: Additional Information / Notes for the ATO.