Audio files other than 32-bit float WAV must be converted on import. Pro Tools | First automatically converts these files to 32-bit float WAV files on import. Also, if the project is not enabled for Interleaved files, Pro Tools splits interleaved audio files into multiple mono files on import.

If clip definitions are present in an audio file, you can convert and import the audio for a clip without importing the entire parent audio file using the Import Audio command.