VLC Media Player is the best tool for this job. It supports native AMR playback without needing extra codecs.
AMR files are incredibly small compared to MP3s. skachat pesni v formate amr
If you have successfully downloaded or converted your files, you might find that your default media player struggles to open them. Here is how to play them on current hardware. VLC Media Player is the best tool for this job
Websites like Zamzar or CloudConvert allow you to upload an MP3 and download the AMR version in seconds. or use VLC for Android.
Look for advanced media players on the Google Play Store, or use VLC for Android.