Hi JoshM! Yes, this unit does have a child lock and according to the manual, this unit will lock when filling with water. However if you need to add clothing you must deactivate the child lock.
For further assistance, I have provided the link to the user manual. Please see pages 34-39.
(https://downloadcenter.samsung.com/content/UM/202101/20210125163747452/WA3000A_DC68-03850F-00_EN_CFR_MES_R_071220.pdf)
Thanks for choosing Samsung. ^Nic