Audacity is a free audio-editing software. Musicians and podcasters use Audacity, but you will likely only need a few of the many features it offers. Below are some resources for beginners.
The tutorial below goes through some of the basics steps in creating an audio recording including opening the application, editing content, adjusting volume and the microphone on your computer, and saving your audio work. It’s a good place to start, but the tool bar is from an older version of Audacity so the buttons are in a different order than the newer versions. (Note, video content ends at 5:11).