Audacity is a multi-track audio recording program that you can use to record brief audio messages or even complete music demos. If you record using your computer's built-in microphone, you will not achieve professional recording quality. For serious recordings, you will need to connect an external microphone, like a condenser microphone or a dynamic vocal microphone. Audacity allows you to configure your external microphone with the software.
Connect an external microphone to your computer. If you have a USB microphone, just connect it to your USB port (the USB symbol looks like a trident). If you have a stereo microphone, you can connect it using a TRS-to-USB cable or a 1/4-inch-to-1/8-inch stereo cable. If you have an XLR cable, you can connect using an XLR-to-USB cable. You can find all of these cables at your local music supply store and in some electronics stores.
Open Audacity, which you can find under "All Programs" (on the "Start" menu in Windows) or in your "Applications" folder (inside the main "Macintosh HD" folder in Mac OS X).
Click the "Audacity" menu at the top of your screen, on the far left side of your menu bar. Select "Preferences" from the drop down menu and finally click the "Devices" tab.
Click your mouse inside the "Recording Device" submenu and select your microphone from the list. If connecting via USB, you should see the name of your USB microphone or USB cable adapter. If connecting through your "Line-In" port with a 1/4-inch-to-1/8-inch cable, select "Built-in Audio" or "Line In" (Mac OS X users may see the words "Core Audio."). Click "OK."
Click the "Record" button at the top of your Audacity window to begin recording through your microphone. To increase or decrease your input volume, drag the "Input Level" slider to the right or left respectively. It appears as a horizontal line near the top of your Audacity window and features a small microphone icon.