The D1 R32 is an (Arduino) Uno alike development board created around ESP32 WROOM-32 chip, containing voltage regulator, USB programmer circuit for ESP32 chip, and a many other features.
For appplication development there is a choice between Arduino IDE or ESP-IDF (Native platform). Most users choose the Arduino IDE because of its simplicity and compatibility. The Arduino user community is very active and supports platforms such as ESP32.
The D1 R32 comes with a pre-installed firmware which allows to work with the interpreted language, sending commands through the serial port (CH340 chip). The ESP32 boards are one of the most used platforms for Internet of Things (IoT) projects.
The D1 R32 board is designed to work with different peripherals and has compatiblity with some shields designed particularly for this board. It has a voltage regulator that allows it to feed directly from the USB port or the socket for a DC jack. The input/output pins work at 3.3V. The CH340 chip is responsible for USB to serial communication.