hi, i made a guitar solo for another guys composition. he use different daw which his project is 16 44.
should i export my solo from my sonar into 16 44 or 24 44 for him to put it into his 16 44 different daw?
what should be better without losing too much sound quality? tx

Whatever you export it at will be turned into 16 bits in the other DAW, so it doesn't really matter. The extra bits will be ignored. However, if you recorded at 24 bits, then if you dither when exporting to the lower resolution the quality will be better - in theory. Whether it's noticeable in practice is another matter, because if it's an electric guitar, the noise floor will be high enough that you could probably capture it with 12 bits of resolution 

It literally doesn't matter. Like Craig says, it's going to end up 16-bit data at the other end regardless. I'd export it as dithered 16-bit data because it'll be a smaller file to send over.