Sparkfun HIH4030 library: https://github.com/sparkfun/SparkFun_HIH4030_Arduino_Library
I think this sensor needs a low voltage, high frequency signal, and a circuit to convert it to analog. It is possible to use it as a resistive sensor with 5V, but then you might have to calibrate it yourself, or maybe you can find a table that someone else has made. However, it should not be used as a resistive sensor with 5V, it should be used with a high frequency according to datasheet.
A table is here: https://forum.arduino.cc/t/hr202-humidity-sensor/140383
They call this sensor "horrible" and I agree with that.
The sellers that sell this sensor to Arduino users just don't care. Please don't buy from sellers that piss on you but buy from sellers that care: Arduino Store, Adafruit, Sparkfun, Pololu, and others.
So if you want to know the humidity, then use a normal humidity sensor for normal indoor use: https://www.adafruit.com/product/4885 or one that has almost everything: https://www.adafruit.com/product/5046