The uncompressed and unformatted string of bytes (for 8-bit sampling) or words (for 16-bit sampling), representing the values of consecutive signal samples, is usually referred to as the raw PCM audio file.
In order to change a raw soundfile into a wave file you have to indicate recording details such as the sampling rate, sampling resolution and number of channels. If you import a raw soundfile from an unknown source you may need to experiment with record settings in order to find the appropriate ones.
In order to speed up format conversion check the Fast format conversion box in the Preferences dialog available from the Options menu.
When performing the fast RAW to WAV conversion the system will simply change the extension of the selected RAW file to WAV and replace its first 44 bytes with an appropriate wave header.