How does LDO voltage work?

How does LDO voltage work?
For this signal we need to measure 4 pins:
LDOREFIN (Low Drop Out Reference Input)
EN_LDO (Enable Low Drop Out)
LDO (Low Drop Out)
BYP (Bypass)

The first signal to consider it is LDOREFIN, this is an input pin responsible for program the output voltage on LDO, when this signal id conected to GND (0v) the output pin LDO will have 5v.
When this signal is connected to a 5v power supply, the output pin LDO will have 3v.
The second signal to is EN_LDO, this is an input pin and i will not extend the explanation of the voltage that will this pin because it depends on motherboard architecture, this signal is LDO Enable Input. The LDO is enabled if EN_LDO is within logic high level and disabled if EN_LDO is less than the
logic low level
The third signal to consider is LDO itself, this is an output signal, this output pin will be 5v if the LDOREFIN it´s connected to GND, and this output pin will be 3v if the LDOREFIN it´s connected to 5v.
The fourth signal to consider is BYP, the name says it all Bypass, this pin will bypass trough 5v and 3v on LDO. If LDOREFIN is connected to GND this pin will be connected to 5v (as showed on picture), if LDOREFIN is connected to 5v this pin will be connected to 3v.