[cpbotha]

The Signal private messaging app has a built-in dedicated "Note to Self" contact which you can text, send photos to, send voice notes to, or share anything with via your mobile OS of choice.

I should have added: The idea is that you use Signal only for quick low friction capturing.

In my case, I later process these messages during my daily input review, at which point they mostly end up somewhere in my Emacs orgmode-based system.