How to use the enable Pin and Error Flag Pin of MIC29301 12V regulator with an Arduino
Always refer to datasheets for the information you are looking for.
From the datasheet:

On the MIC29xx1 and MIC29xx2, the ENABLE pin may
be tied to VIN if it is not required for ON/OFF control.


CMOS compatible control input. Logic-high =
enable, logic-low = shutdown.


MIC29xx1 and MIC29xx2 versions feature an enable
(EN) input that allows ON/OFF control of the device. The EN input has TTL/CMOS compatible
thresholds for simple interfacing with logic, or may be
directly tied to ≤30V

So, you can control the ENABLE pin using digital output of Arduino directly.
Also from the datasheet:

Active-low error flag output signal that indicates an
output fault condition.


Error
Flag, which looks at the output voltage and signals an
error condition when this voltage drops 5% below its
expected value. The error flag is an open-collector
output that pulls low under fault conditions. It may sink
10 mA.

Since FLAG is an open collector output, you have to put an appropriate pull-up resistor. You can then read the FLAG pin using digital input of Arduino.