When you paste content into the editor, you often bring ‘loads’ of invisible formatting with you, and this can have consequences that you don’t want to show on your post or page when viewed by the public, such as strange fonts, text sizes and other formatting.
For those who’d like to know more…
When you want to paste content into your post or page, click the “Paste as Plain Text” icon, and when the popup appears, paste your text into the text box, then click Insert. This will remove all of the formatting, leaving just the text.
It does mean that you will have to re-apply any formatting that you wanted, but it will most likely turn out for the best in the long run.
If you’re taking content from another website, or from Word or some other type of document, you will usually be ‘copying’ all of the formatting that goes along with the text, and when you paste that directly into the editor, all of that formatting goes in to, but a lot of it may not show up much in the editor, but often will when you are looking at the post or page in the public view.
The other issue, and it is probably the biggest pain, is that this pasted formatting will often prevent you from being able to change the formatting of some of this text.