Composing! That's what I'm up to these days. I still use pen and paper. It can begin anywhere, often at the piano, but not always. Sometimes at a guitar. Sometimes when I least expect it and I'm not near any instrument. Whenever and wherever it begins, I write it down. Then I edit. Then I mull it over, also known as obsessing over it. I play it. A lot. I decide to push a little harder at getting the melody just right. I change one note. I practice playing it. I begin thinking about an arrangement, an orchestration. I write that down, too. I have a lot of rough sketches. Once they get so rough I can't read them anymore, I rewrite by hand. Then, maybe, I'll put it in Finale if I need clear parts.
Then I record.
Recording has become a given for composers. "I'm not an engineer," I used to say. Now I record. I have a studio. I upgrade my gear. Did I really just write that? Yes, and I'm having the time of my life doing it.
But I always write it down first. That doesn't change.
Then what becomes of the music (to paraphrase an earlier song title of mine)? It goes on to spend its days serving various purposes for people. It becomes an unseen character in an onscreen ensemble. It predicts an emotion, or it responds to an emotion. It adds elegance or humor to a visual story. Or it is something that you drive or walk around with as you go about your day.
As long as I tune into my mind's ear and write down a snippet or two every day or every couple of hours, I'll keep 'em coming for you.