Audacity creates two types of files, so it’s important to distinguish between the two.
When you click ‘Save’ within Audacity, it saves what’s called an Audacity Project file. This has the file extension .aup.
The .aup file stores all the information on the edits you made to your original recordings, the music and SFX you’ve added and any other information about the audio project itself. This isn’t an audio file though. It’s just designed to store editing information, and make further edits to the project in future. To get your audio file, you need to Export an MP3.
Creating Your MP3 Audio File
To create your MP3 audio file, click on the File menu, and then Export, as shown in the image below.
This bring up a box which allows you to choose where to save your audio file, and what to call it. It also allows you to choose the format of the file. This is important, as you always want to make sure you’re exporting an MP3 file.
Click the ‘Save as Type’ dropdown, and make sure you select MP3, as shown below.
Once you’ve selected MP3, and chosen your name and location, click Save. Audacity will then proceed to export your audio file in the correct format.