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https://forum.noteworthycomposer.com/?topic=1183 should answer your question.
(vist me at www.sosyourmom.com/Oneils1.html)
I found this description on Kurzweil's (they make keyboards) site, in response to the same question:
"Type 1 files contain separate information for each track. For a Type 0 file, however, all the tracks are merged into a single track, although MIDI channel information is still retained. When a Type 0 file is loaded into a sequencer, it will take each channel's information and put it on a separate track. So for a typical sequence with one track per MIDI channel, it will normally not matter if the sequence is saved as Type 0 or Type 1. But if your source sequence has several tracks assigned to the same MIDI channel (for example several drum tracks playing the same program on the same channel, but with an individual drum sound on each track), then it is best to export it as a Type 1 file. If exported as Type 0, all tracks assigned to the same channel will be merged into a single track when the .MID file is loaded."
Generally, type 1 MIDI's are more versatile; however, some devices (such as keyboards) will only accept one or the other. My Kurzweil Digital Piano and my Casio WK-3500 keybaord only accept type 0 files. However, if I'm ever going to do anything with a MIDI file (such as convert to WAV audio), I will also save as type 1 and use that in my sequencer program.
Noteworthy Composer can convert and save you NWC compositions in both MIDI formats.
Hope this helps.
John