To facilitate online transmission, the prepared WAV files need to be converted into smaller formats such as MP3 or RM; otherwise, they are not only prone to buffering during playback but also take up a lot of space when uploading. Use the Windows built-in Recorder. Don't underestimate this little tool; for many beginners, the recorder is the easiest tool to get started with. Open the WAV file with the Recorder, select "File" - "Save As", there is a "Change Button" at the bottom of the "Save As" dialog box. Click this button, and we can change the file format.