An M3U file is a simple, plain-text based file that acts as a musical shortcut file. Once set up, you can double-click an M3U to launch a playlist of songs in a certain, specified order. While you can get third party applications to create M3U files, you can create one with TextEdit. TextEdit is the text editing application that comes with the Mac operating system.
Click "Go" in the Finder's menu bar and then select "Applications." This will open the Applications folder. In the window that opens, scroll down to the "TextEdit" application and double-click the icon to start the application.
Click "TextEdit" in the menu bar and then select "Preferences." Click the "Plain text" button in the Format section of the New Document tab. Close the Preferences window. Press "CMD"+"N" to create a new document in plain text.
Type "#EXTM3U" (without quotes) in the first line of the file. This tells your operating system that the file is an M3U playlist.
Use the following example throughout the rest of the file to create your playlist: #EXTINF:999,Artist - Song Title songtitle.mp3
In this example, change "999" to the number of seconds that the song plays for. Change "Artist - Song Title" to the title and artist used for the song. Replace "songtitle.mp3" with the file name of your MP3. When creating M3U files, it is easier if you include all the songs within one directory, otherwise you need to put exact paths to the file, for example "/desktop/music/artist/album/songtitle.mp3"
Repeat for all the songs you want to use.
Click "File," then "Save As." Enter a title followed by ".m3u" as the extension. Click "Save."