The simplest way to convert files to or from WMA format is to use an online converter such as media.io or online-convert.com. To use media.io, navigate to the website, click the Select Files to Upload button, and choose the files. Then select an output format, and click Convert.
To use online-convert.com, visit the website, and choose the file format to which you want to convert from the sidebar on the left. Click the button to upload an audio file, or enter the URL of an audio file. Choose the output settings, then Click Convert File.
Alternatively, media.io is also available as a free download for Windows. This offers the same functionality as the online version but is faster and easier to use for multiple files.