self-certification
noun [ U ] UK formal uk/ˌselfˌsɜː.tɪ.fɪˈkeɪ.ʃən/ us/ˌselfˌsɝː.t̬ə.fəˈkeɪ.ʃən/
（尤指在税收或疾病方面的）自我证明
an official statement that you make about yourself, especially in connection with tax or illness
You are able to notify up to eight days' illness by self-certification. 请8天之内的病假，自己证实病情即可。