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, but like I said, it’s LoLin’s version of Nodemcu and not the original, official board. Pin-numbering, amount of flash and such things are the same. Though, with the LoLin-version you can use the faster QIO-mode for the flash instead of DIO.