edit volume of an imported audio file

I am a novice with audio software. I see that we can cut and paste the imported audio files.
But I want to decrease the volume in specific sections of an imported file.

Since the cut & paste procedures are manual ( visual, horizontal ), :question:
I hoped that volume amplitude was simply a manual visual horizontal action also.

I cannot locate any reference to volume editing in the EDIT drop menu.
Comments are requested and much appreciated.

One way is to use the Envelope Tool: http://manual.audacityteam.org/o/man/envelope_tool.html

Another way is to use the “Adjustable Fade” effect: http://manual.audacityteam.org/o/man/adjustable_fade.html