How to convert files to Winamp format?
do you mean .mp3 or another format?
Winamp has support for many audio formats but if you have one that is not supported by Winamp, you can use MediaCoder to transcode it to MP3 which is the default format supported by Winamp.
you could use tools like any video converter to convert all files to either mp3 or mp4.
Both are supported in winamp.