Hi Jululian, hope you are well
Text on internet pages are often contained within frames, if you've selected
the whole paragraph or more than one paragrapgh from a web page there's a
good chance the frames were copied to the clipboard as well.
Here are a couple of options:
1. Keep your selection tight to the paragraph of text, make sure the
highlighted section of the web page are just over the text only, then copy
this information to the clipboard. This should avoid copying the frames
surrounding the text into your word document.
2. Copy the information from the web page onto the clipboard, and then use
the Paste Special function to paste the contents into a new word document.
I'm not sure which version of word you are using, however in Word 2003 this
option is available via the Edit Menu -> Paste Special... -> select
Unformatted text -> Click OK.
Hope this helps, and you are able to find a solution in here.