How do I Play a M4A sound file???

Hi, i cant play a m4a file, for example.

i put "on touched button, play X song"

and in the "audio files list" doesnt appear my M4A files but it appears my MP3 ones. Why?

You should always have an M4A and OGG file. It is an oddity that the OGG will show up without M4A, but not the other way round.

Was there an import conversion error?

It is sometimes preferable to convert before import using something like Audacity.

so i should use a OGG and a M4A, but use the OGG in the events?

You don't actually pick the extension, it's just the base name & C2 calls the appropriate one.