This is the most common problem faced by beginners who have purchased an Arduino or NodeMCU module. These modules usually have a main microcontroller IC which connects to USB interface with the help of an Serial to USB interface IC such as CH340 or CP2102 to connect it to computer and program it with the help of IDEs like Arduino IDE software or PlatformIO IDE.
90% of such issues occur due to lack of proper drivers on computer OS for these Serial to USB interface IC. This Serial to USB IC is usually specified by the module sellers/ sites or you have to figure out by reading engravings on the IC. Once the IC is identified we have to search on internet for suitable drivers for the installed computer system and download it.
After successful installation of downloaded driver when we connect our Development Module to computer using an USB cable an Serial Com port (like ”Com1″ in Windows OS and “TTY01″in case of Linux OS) is assigned to our Development Board. Now we can select this com port in Arduino IDE and program the connected module.