what is channel in esp32 pwm ledcAttachPin(GPIO, channel) function?
What is the significance of the 16 channels present?
Does each has different role?
You can learn more about the ESP32 PWM channels on the ESP32 datasheetpage 26 and 27: https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf
You can chose whatever channel you want to produce a PWM signal. You need to specify the channel because you may want to generate different PWM signals with different frequencies at the same time.
In that case, you need to chose one PWM channel for each signal. So, you can generate up to 16 different PWM signals using those channels.
I hope this helps.