An iPhone Voice Memo is an M4A file, and M4A is not always welcome in professional tools. Some audio editors, transcription services, dictation software, samplers and video editing workflows want plain WAV, or import M4A only through extra plugins. Converting to WAV removes that friction. This page opens with WAV as the output; drop the M4A files and convert, and you get 16 bit, 44.1 kHz stereo WAV that every program opens. The WAV will be far larger, around 10 MB per minute against roughly 0.5 to 1 MB per minute for a typical voice memo, because it is uncompressed. That size buys you nothing in sound quality, since the AAC compression in the M4A has already decided what was kept, but it does mean that editing and re-exporting will not add any further loss until the final step. The exception is M4A files holding Apple Lossless audio, which convert to WAV with no loss at all. Copy protected files, such as Apple Music downloads, cannot be converted. Everything runs on your device, so recordings of meetings, interviews or lectures never leave it. For a smaller, more shareable file use M4A to MP3 Converter, and to get the recording as text use Speech to Text Audio Transcriber.
The split that matters most in audio formats is lossy against lossless. A lossless format such as WAV or FLAC stores enough information to reconstruct the original waveform exactly, which is why WAV files run around 10MB per minute of stereo CD quality audio. Lossy formats such as MP3, OGG Vorbis, AAC, and Opus use psychoacoustic models to discard sound that listeners are unlikely to perceive, typically hitting a tenth of the size for audio most people cannot distinguish in normal listening. The important consequence is that the discarded information is gone permanently. Converting MP3 to WAV inflates the file back to full size without recovering anything, and each further lossy conversion compounds the loss, an effect known as generation loss. The practical rule is to keep a lossless master and export lossy copies from it, rather than converting between lossy formats repeatedly. Bitrate is where quality and size are actually traded. At 128 kbps most listeners cannot reliably distinguish MP3 from the source on laptop speakers or earbuds, though the gap becomes audible on good headphones with dense music. At 256 to 320 kbps MP3 is effectively transparent for nearly everyone. OGG Vorbis reaches similar quality at a somewhat lower bitrate, because it is a newer design than MP3, and Opus does better still, which is why messaging apps and voice chat use it. Sample rate and bit depth apply to the uncompressed side. This tool writes WAV at 16 bit and 44.1 kHz, the CD standard, which is the format editing software and mastering workflows expect, and which every audio application on every platform can open without conversion.