How can you copy buildings in Minecraft?

Hi, I wanted to copy a building in Minecraft, but I don't know how it works.

PS: But it must not be a plugin because my server does not support plugins. But a mod or a command is ok.

I can only think of worldedit. Why does your server not support plug-ins?

There's an order! Search it on Google or something because I don't know it by heart

You can mark your building with worldedit and then simply enter // copy. Your server needs Forge, Magma, Bukkit or Spigot for this

Yes I worldedit the best for something like that

Try the / Clone command.

Either you use struckture_block or / clone