how to activate immersive reader on iMac 27" 2015 OS BigSure

Hello Community

I'm currently studying for a master's and have a huge amount of reading to do. My eyes are getting tired and sore with all this screen reading. Is there any way to have a PDF document read out loud so I can take notes by any chance? Is anyone able to give me some pointers, please?

Thank you very much in advance.

Have a great weekend.

Fred