If your wav audio files are large they can take a long time to upload to your transcription services provider. wav files can also take up a lot of space on a hard drive.
To combat this convert the wav to mp3. Converting the wav to mp3 will compress the file to a smaller size. The audio file will then be quicker to upload to your transcription services provider over the internet.
There are hundreds of file converters to choose from on the internet although the file converter I mainly use is Switch Audio File Converter Software, which is really easy to use.