self-certificationnoun [ U ]
uk/ˌselfˌsɜː.tɪ.fɪˈkeɪ.ʃən/us/ˌselfˌsɝː.t̬ə.fəˈkeɪ.ʃən/UK formalan 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.