You can actually bootstrap a small text editor on mobile browsers using a data: URL and a tiny text editor in html (literally just a form with a text box that will download a file with the contents of the box when you hit submit).
A pain, and not accessible if you don't know the google incantations to figure it out, but doable.
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Open a browser and you have JS built in. To me, that is pretty accessible. Maybe on a phone you might need an app.
You can actually bootstrap a small text editor on mobile browsers using a data: URL and a tiny text editor in html (literally just a form with a text box that will download a file with the contents of the box when you hit submit).
A pain, and not accessible if you don't know the google incantations to figure it out, but doable.