Copying from word usually brings a bunch of extra ‘stuff’ Microsoft hides from view...to get a clean text, first copy your text into a text file (this will strip out all the unnecessary code and give you a clean text), then you can paste in your description and add your formatting. If you know HTML you can get a little fancier - click on the “ < > “ icon to view the HTML code.

Another option when you are pasting the text into the field is to paste as plain text.  Once the text is in the field you can then format accordingly.