The Octopi distribution of Raspian Lite which is meant to be an easy way of setting up an Octoprint server for controlling 3d printers requires you to edit a couple of files in the boot partition. They provide explicit instructions on how to do this. Since the boot partition can be read and written by Windows, Linux, and Mac computers, it is easy to find a computer to do this.
They do require that you use, on Windows, a programming editor that understands that "/n" is a newline. They list notepad++ as one of them. There are many free editors that can do this. I would have run a script first that would have fixed the file that Windows could have munged, but that's just my opinion.
The files are octopi-network.txt and optionally creating an empty file called ssh or ssh.txt.
The octopi-network.txt file has everything needed to setup a wireless network and creating one of the ssh files will activate ssh at startup.
I do not think that requiring somebody to have an unlocked WiFi access point is reasonable. It is opening up a large security hole. I also would not give my network information to somebody who wasn't a personal friend.
It would be much more reasonable to allow ethernet access. Almost all wireless routers have ethernet ports, and all technical companies have ethernet wired.
If the Raspberry Pi is installed inside a device, it wouldn't be difficult to put an ethernet port on the outside of the device and run a short connector to the ethernet port of the pi. I did something like that for a robot I built once.