Writing transposing Instruments in MIDI

Hi everyone, 

I am am new to composing and I’m sorry if this is such a basic question but I searched and I couldn’t find anything about how to treat transposing Instruments when writing music. For example, I learned that if you play a C on a clarinet, it sounds like a Bb. Does that mean in MIDI I should write a C in the piano roll if I want to hear a Bb, or will the DAW adjust for transposing Instruments automatically? (I use Logic Pro X btw)

My second question is if I take the score my DAW gives me, print it out out, and give it to a clarinet player... how do I know they would play the right notes? Is it just me or is this confusing? Thanks much your help is appreciated!