In fact, if you're okay with only editing/creating password entries on your phone, you don't even need to pay for the desktop app, because you can use it in read-only mode. The Android app has no limitation to editing local vaults, and it's pretty rare for me to actually have to set up new accounts these days, so I'm fine doing it on my phone. I considered paying for 1Password X (their online offering), but it's simply not worth $45 per year for that minor convenience. I can't complain at all, because I use 1Password completely for free.
It's possible that it was hidden because I had previously signed in to my work's 1PW account, maybe, or that it's hidden too well for me to find. I don't know, and would be happy to learn either way.
https://pwsafe.info/ for Mac and iOS https://pwsafe.org/ for Windows
The underlying file format is opensource and developed by Bruce Schneier.
I use it to securely store notes and important files.