If you want to do some editing of audio files, download the free application Audacity. Audacity has a range of sophisticated options. You can easily export clips of audio files, record new files, and add tracks to existing files. A good example of Audacity's editing abilities is the Noise Reduction tool in the Effects menu. It allows you remove background noise from a recording, such as tape of a conversation made outdoors.
You first need to identify a portion of the recording which only contains the background noise you want to remove.
Select that area, and then go to Effects . . . Noise Reduction. A dialog box will open. Click where it says "Get Noise Profile".
Now select the full range that you want the background noise removed from and go back to Effects . . . Noise Reduction. Accept the default setting and click OK. You should see a noticeable reduction in the background noise.