In the past, I have been doing lots of technical documentation using AutoCAD and MS Word. Transfering drawings was nearly plain Copy/Past from ACAD to Word.
I have tried to take a small drawing from LibreCAD to Write. No way I could make that work. I have tried several ways to copy the drawing but nothing shows up on the Clipboard. For me, LibreCAD will be useless without the ability to fast and simple transfer small drawings into a advanced text editor like Write.
As Humulus' s answer shows you can also use screen shots. Zoom in so that the desired section will have roughly the appropriate pixel extension needed, do the screen shot, insert it in a bitmap processing app (I use Irfanview, very handy for this task), cut it down and send it to the clipboard. There also are extra sceenshot progams where you can shoot a selected screen area directly.
From LibreCad you can't copy vector content to the clipboard, only within LC.
If you desperately want/need copy and paste directly to Word or similar, you may try Draftsight. It's free but not open source, it does basically what you seek.