But you omitted what your PC is so my answer will be generic.
Head to your laptop maker's page on drivers and apps and look for their OSD or control apps. I can't use the words the maker uses since, you left out key details.
My OS Wins 10 Pro Ver. 1903 display adapter Intel (R) HD Graphics 4600. My system is operating perfectly but I can'[t locate or get to my "brightness adjustment'. I'm thinking something must have gotten disabled .