How do you reduce 32volts to 12 volts?

Answer 1

To reduce 12VDC to 7VDC you need a voltage divider in the ratio of 7/12, such as two series resistors of values 5KOhms and 7KOhms.

Of course, this "trite" answer (the resistor divider) depends on how much power you need to supply, and how much source to load current regulation ratio you need.

You might need to follow this up with an class C amplifier, compensating for the 0.6 volt drop across the base-emitter junction.

You might need an OP-Amp controlled emitter follower, with a zener reference.

For high current applications, you might even need a switching regulator.

Answer 2

That depends on the application.

If it's 32 volts alternating current, you can use a transformer.

If it's 32 volts direct current you can use a solid state regulator.

Either way, if you want to go quick, dirty and cheap, you can just use a resistor in series with the load.