WAV (or WAVE) is actually the first full-fledged audio format with good sound quality. It was developed quite a few years ago by the joint efforts of Microsoft and IBM. Sometimes this format is even called “Audio for Windows,” because it is the standard for storing audio stream for a traditional Windows desktop computer. Full name - Wave Audio File Format. The short name is derived from the English word wave ("wave"). The peculiarity of this format of digitized audio stream is the lack of compression. WAV files take up too much space, but it is ideal for storing high quality files in their original form.
M4R is a highly specialized audio file format. This format (full name - iPhone Ringtone File) was developed by Apple's IT giant specifically for the iPhone. This format creates music ringtones for the iPhone. ITunes Ringtone is the main program for opening files with the extension .m4r, and their creation is mainly using Apple iTunes. Formally, M4R files can only be created from songs and other works purchased in the iTunes music store. The size of the created ringtone in the M4R format can be a maximum length of not more than 40 seconds.