I want to implement voice mute function in C language

As I mentioned in the comment, handling voice is very difficult.

• Somehow controls the whole thing
• The application controls which voice it makes
• Control voice for specific other applications
  (e.g., mute browser audio)
• Controls the output of a specific device
  (e.g., mute audio output during a call)

You need to specify what you want to accomplish.For your information, I'll give you a rough idea.

Some laptops and multimedia keyboards have mute keys.Therefore, Windows pre-embedded the action to be taken when the mute key is pressed (even if the keyboard is not connected).
This method will only cause unmute and unmute to toggle.This method is not available when it comes to understanding the current mute state and taking action according to the state.Also, since it's just a key operation, a pop-up will appear on the screen to indicate the state of the voice.

Emulating the mute key from the program will result in unmute and unmute.Specifically, you can pass the SendInput function with VK_VOLUME_MUTE.

INPUT input={INPUT_KEYBOARD, {VK_VOLUME_MUTE}};
SendInput(1, & input, size of input);