If you are using the Arduino development kit to program your board then these values are already defined by the pins_arduino.h for each esp variant and will be included in your code automatically, along with any other pin labels like RX TX etc.
That’s great if your board matches what boards are listed. The Lolin esp8266 isn’t listed. Based on your comment. I searched for pins_arduino.h (I found a bunch). I went through each one and the LoLin pins match the Wemos D1 Mini. Now that I know that, I can choose that in boards, and don’t have to specify the pins. Thanks!
@Steve_Spence Yes, it is. The LoLin-board is just their version of Nodemcu, which does exist there.
@Nita_Vesa The Nodemcu has a built in LED I believe, where the LoLin does not. Am I correct?