Do Structure Blocks in Minecraft Save Permanently?

Solution 1:

I don't understand all parts of your question and it seems that your confusing structure blocks with some thing that can help you finding generated structures (it doesn't do that, only /locate does that, as well as ender eyes and explorer maps), but yes, structure blocks always save to a file immediately (unless you have some weird permissions problem in your world folder, which shouldn't happen). I don't know where you found information about it just using RAM, but I have a vague memory that that used to be a thing way back in a few snapshots. But that has long changed since then.

The default location, when you just save a structure called "example", is %appdata%/.minecraft/saves/<world_name>/generated/minecraft/structures/example.nbt, with "<world_name>" being the name of the world (folder name, not in-game name, so it could also be "New world (2)" even if your world is named "New world" in-game).