I have 2 easy drivers, 2 stepper motors, one servo and an Arduino. I have it all coded and it works but I want to minimize the power so I have 12v running to one easy driver 12v running to the other one 12v running to the servo and 9v battery to the ardunio. Can I take a 36v power supply and plug the 2 easy drivers and the one servo right into that, will that work and power it correctly or will it over power it?
No! 36V makes no sense. If you have 3 devices that need 12V (though I’ve not seen many 12V servos) then connect them all to one 12V supply in parallel. The 12V supply needs to provide enough current for all of the devices.
With power supplies you need the correct voltage and enough current. If different parts need different voltages you need multiple supplies, or to derive one from another using a DC-DC converter or linear regulator.