multiple voices dont work , 3.6 macOSx

Attach a score and add details (step by step how you enter Voices).

The most common mistake people make is trying to select a voice before entering note input mde. That doesn't work; it's the other way around. Selecting a voice when not in note input mode does something different - it moves the selected note(s) into the chosen voice.

If you continue to have trouble, please attach your score and describe more precisely what you are doing and at what point something appears to go wrong.