What is the best document to read and refence on the general configuration of the PLLs and PFDs on iMXRT architecture (iMXRT1062)?
I hope you are well.
In the reference manual, you can find detailed information about clocking.
This document can also be helpful since it contains summarized information about the reference manual: RT's System Clocks - NXP Community.
If you have more questions do not hesitate to ask me.