When you copy a section of a web page, all of the HTML tags (things in < >) and all of the text are put on the clipboard.
When you paste from the clipboard into a
Text Box (like a Forum New Topic box or Reply box) the HTML tags are stripped out, and only the text goes in. So images and hyperlinks and text formatting are lost.
You can then use bbcodes to put the images and links back in, but it can be a lot of work.
To preserve the HTML tags, the clipboard has to be pasted into an
HTML box, where it will look like the original web page.
You can then tidy it up, if necessary, and then view the corresponding bbcode.
Now if you copy that, you can paste it into a New Topic box and all the images and hyperlinks will be there.
You will find an HTML box at
https://www.doomsteaddiner.net/palloy/sceditor/htmlbox.htm(You might want to Bookmark this page).
It might save you quite a bit of time on some web articles.