You can copy and paste documents into FR threads???
I always just find them online and use html tags IMG SRC
To do a proper copy you can highlight the icon for the file and use keybaord shortcut CTRL-C to copy it to your clipboard, then CTRL-V to paste it where you want the copy to go. Or you can right-mouseclick the file, and select copy from the fly-out menu (it may be buried under “More Options” in the latest version of Windows-11 right-click menu).
If it’s a .DOC or .XLS(x), then it will want you to have a (paid for) working version of Office apps to open and edit them.
I'm probably not using the correct terminology for what I do. I too use the IMG SRC tags, as part of creating a variety of the fund-raising posts that I use on the FReepathon. I incorporated that into info that includes the donation link, and then saved those kinds of creations in my documents folder for later repeated use. All I had to do was copy and paste, without recreating the whole thing each time. I can't copy and paste those existing creations anymore. (Hope that makes a little bit of sense.)