In this tutorial I will show you how to create a basic triangle in 3ds max. Although for some this is obvious, I hear that a lot of begginers are having problems finding the exact command location.
This happens because the name of the button is not called triangle, but NGon.
You can see it in the image below:
After clicking it, on the parameters you have to input the value 3 on the sides textbox.
Then you click and drag on the viewport and the hidden triangle is created.