Encode - default action. Input files will be transcoded to the destination format. See Encode Settings.
Extract - audio stream will be extracted from the input files (if that is possible). No transcoding will be done and no quality will be lost as a result. See Extract Settings. This is mainly used to extract tracks from lossy encoded source (e.g. mp3, aac, ogg). Please use encode for lossless audio (e.g. WAV, WavPack, FLAC, ALAC).
Merge/CUE - added files will be merged into one file. See Merge/CUE Settings.
Split into file per channel - each added file will be split into n mono files and encoded to the specified format (n - number of channels of the input file).
Encode to multi-channel file - all added files will be encoded to one multi-channel file. Channels will be assigned by the order files are added. File must have the same length, sample rate and sample format.
Copy - copy files to the destination folder using pattern specified in Copy pattern (see Patterns). No transcoding will be performed, files will just be copied. Please don't confuse it with "Extract" function, where audio is extracted from the source file without transcoding.