Does the 433 MHz transmitter/receiver, transmit the voltage?
These 433 MHz transmitters use OOK modulation (also called ASK), making the transmitted signal look like:



So the transmitter is simply switched on (1) or off (0).

Most 433 MHz receivers will "filter out" the 433 MHz so we're left with the blue signal.

When no signal is received for some time, most receivers will try to decode a signal from the noise they receive and the noise from the receiver itself. That then results in a random 0 / 1 pattern.

To do something useful with this system that random signal must be ignored and the useful signals must be extracted out. This is a typical job for some software on a microcontroller. You also want a microcontroller on the transmitter side. Then it is easy to create long 0 /1 sequences like: 0010100100111010101101

When you transmit that code, the microcontroller will respond and that will open your garage door while the noise doesn't open the door. Also your neighbor's door will use a different code so the two doors will not interfere even though you would both be using 433 MHz.