Not really a beginner; started when I was 14, I am 40-something now...
Published and all, just getting back into it due to a swelled up heart (in a good way).
Just wanted a consensus/brain picking on how others still write/jot down/remember a song.
Greg Allman wrote ‘Whipping Post’ on a napkin in a thunderstorm...
My songs alway start out on paper. Lyrics expressing an emotion or a story. Then comes the music. It usually happens almost simultaneously..but for me as a songwriter, the words, the story comes first. The music just flows from there. I usually start the music out simple..like a three or four chord melody. I work out the fun chord changes and mixes later on or with others.
Or I record the roughs in Garageband. If you want to get real sophisticated you can step into Logic Pro or step out of major composition to other more basic songwriting software.
If I have to jot something on notepad on my iPhone I do ALOT! I'm a singer and musician so I have a home studio with keys, baby grand, guitar, congas and lots of staff paper. I am old school and also a novelist etc. So anything that I can write on or that can record a melody works.