I don't keep a diary/journal because I don't find the everyday, factual details of my life interesting, nor do I remember many of them. I might find it depressing actually. It would be like "boring, boring, mundane, more boring".
I do write crap poetry & I do type it out because I'm lazy & it's easier. Sometimes I use a notebook too. Whatever's easier & close at-hand. Sometimes what I write is related to what I'm currently feeling, but it's rarely triggered by specific events & is often more of a general concept reality may have inspired.
I do currently have a journal I am scribbling non-sensical crap about enneagram into. I write in it because it's easier to use than my laptop when curled up at the foot of my bed where my feet go when I sleep, which is how I like to think about enneagram.
Any other INFPs have physical modes for different ways of, er, processing?
I like pacing for thinking "analytically" or working out how I feel in a more thinking-way. Used to drive my family crazy by pacing constantly. I'm on my stomach with paper for creative writing & drawing. Ideas can actually cause a physical burst of energy, like running around or jumping up suddenly. Typing like a madwoman is best for for ranting & raving & emotional spewing. Something about the keyboard plunking down a bit violently is soothing. I imagine that's part of the appeal of the piano... I should definitely learn to play the piano!