I think there's some potential for confusion here. Regarding key signatures in scores: A score with one sharp is traditionally interpreted to be either G major or E minor. There is no other indication of whether or not the key signature implies G major or E minor unless it is included in the title such as "Polonaise in Ab Minor." (I say traditional because there are non-traditional scoring methods too.) Regarding chords, there are a variety of ways to show chords in a score. For example, a C minor chord can be designated as Cm or C-. A G major 7 can be GMAJ or G^. And so on. Now 7989122's comment about major/minor scales is interesting to me. I've never used a score that does it that way, but it makes sense on a certain level. I don't need that sort of notation in my arranging, but hey, maybe I've learned something new. If you sign up with the Sonic Scores forum (no affiliation) you can ask questions and get a lot of helpful answers from professional musicians. They also know a lot about MIDI. There are other music notation apps that have active forums.