WMA is an abbreviation of Windows Media Audio. The WMA format is designed by Microsoft as an alternative to MP3. The WMA format is characterized by good compression ability and competes with the audio format from Apple AAC. This file format is supported by many portable audio players like the most widespread and common MP3.
M4R or iPhone Ringtone is the format of ringtones for mobile devices from Apple. This is the same format as M4A but with it has several limitations. The duration of the audio stream should not exceed 40 seconds. In case the duration is longer, iTunes does not install the ringtone on the mobile device.