How does the Zener Diode stabilize the voltage?

Zener diodes are used in reverse.
When Zener diodes are used in reverse, they maintain a high resistance value until the breakdown voltage is reached. When the breakdown voltage is reached, the resistance decreases sharply to close to zero. The current should be limited.
The Zener diode works in the reverse breakdown state.
Reverse breakdown generally has two states: avalanche breakdown and Zener breakdown.
Avalanche breakdown is when the reverse voltage of the PN junction increases to a value, the carrier multiplication is like an avalanche, increasing much and faster.
Zener breakdown is that at a high reverse voltage, the strong electric field in the PN junction destroys the covalent bond in the conductor and forms an electron-hole pair, forming a large reverse current. Zener breakdown requires a lot of electric field strength! This can only be done in PN junctions with high impurity concentration. (the higher the impurity, the higher the charge density.).
The reverse breakdown of PN junction includes Zener breakdown and avalanche breakdown, which generally exist at the same time, but Zener breakdown is the main breakdown when the voltage is lower than 5mur6V, while avalanche breakdown is the main breakdown when the voltage is higher than 5mur6V.
For voltage stabilizer diodees, the main differences between the two are:
The Zener breakdown is dominant for the voltage stabilizer whose voltage is lower than 5mur6V, and the temperature coefficient of the voltage stabilizer is negative.
The avalanche breakdown is dominant for the voltage regulator diodee whose voltage is higher than 5Mel 6V, and the temperature coefficient of the voltage regulator diodee is positive.
Sometimes the components of two voltage stabilizer diodees in reverse series are compensated for the temperature coefficient. When such a voltage regulator is connected to the circuit, there is no difference between positive and negative.
The power of the voltage stabilizer diodee is generally small and can only be used as a voltage stabilizer reference.
Use a single voltage regulator to stabilize the voltage when a small current is needed.