Never paste text directly into editor
The #1 cause of page designs looking bad is due to pasting in code from an external document – like Microsoft Word – directly into the editor.
Microsoft Word is a fine word processor for producing documents to be shared or printed, with a wealth of print-based options for indexing, and producing table of contents. As a web publishing tool, however, it is a little less than ideal and produces very messy HTML because when you copy the text in MS Word, you also copy all the styling features for the print document.
The same applies when using Google Docs, OpenOffice, or other word processors and spreadsheets like Excel.
If you do need to paste content from Microsoft Word, you can do so by selecting your content in your MS Word document BUT DO NOT PASTE IT DIRECTLY INTO the Visual Editor.
Click the paste as Text button as shown above.
Your editor will then be in “plain text mode” so you can paste in your text from Word or another word processor. You will see the following window pop up telling you that you are in this mode until you click on the button again to turn it off:
Once you’ve enabled the Plain Text option once for a post or page, subsequent clicks on the button will turn it on (evidenced by a box around the button) or off (no box around the button). You will not see the pop up window again unless you reload the page or go to a new post/page, but the toggle option still works.