What audio file formats does WhatsApp officially support?
I have not found this information on the WhatsApp website...
You can actually send any file-type, if you know how to do it...
Whatsapp will support many popular audio extension, but particularly which are unknown may be becaz theres no need to.
You can use apps like Whatsapp File Sender allows use to send any file-type through Whatsapp.
The WhatsApp File Sender app uses an ingeniously simple trick: your files, no matter what type they are, will be converted to a voice message that can then be sent without any problem in WhatsApp.
At the receiver's end, the audio file is then converted back to its original format and can be opened and used normally. No data will be lost, there will be no loss of quality.
Free version has limitations: there are no notifications and you can send only one file at a time, which cannot be larger than 16 megabytes.
Apps like Media Converter can be used in case you bump into a audio file type not supported in Whatsapp.
On my phone WhatsApp natively records sound files in .m4a format. I hope this helps.