How do I introduce impedance in an AC circuit?
Please don't, it really doesn't work this way
I appreciate your noob status and it's great that you are asking here ! Connecting a 100V load to a 220V is fairly complicated, a simple voltage divider is NOT the way to do this. And if you get it wrong there is signficant risk of severe damage to the motor or the power supply. Even worse: there is significant risk of damage to people including yourself.
The proper way to do this would be a transformer but if you don't know what this or how to properly specify and size it, you shouldn't be using one.