If you received CERB from Service Canada, the amount repaid will be reported on your T4E slip along with other EI amounts repaid. Service Canada will send you a letter showing the amount of CERB you repaid.
In TurboTax Online please go in the menu on the left-hand side and click on Income then on T-Slips to then find and click on the information slip required and enter the information. Please click Done With to save your entry.