How does structure generation work?

The question is in the title. Does Minecraft pregenerate structures? How does it locate a structure before it is loaded or is it already loaded? I’m trying to generate custom structures although I don’t know how to locate them like how /locate can or if I’m even generating this correctly. The way I’m generating my structures right now is creating my own BlockPopulator, checking/finding if the chunk is valid to generate the structure in, checking the chances of the structure generating, and then generating it.

 

https://letmegooglethat.com/?q=How+does+minecraft+structure+generation+work?
https://minecraft.fandom.com/wiki/Generated_structures
https://www.reddit.com/r/gamedev/comments/16yyqw/how_does_minecraft_generate_structures_especially/

 

I have a doubt. Thank you in advance BTW. I want to spawn a random structure whenever I kill a creeper or an entity.
How do I do that

 

Your best bet is to paste a schematic with worldedit API or (even better) FAWE API.

I mean ofcourse that would be very slow and inefficient, you could do it with just structure blocks