When you copy paste text from a word document or another site into your site it can sometimes copy across HTML styles. This can cause your text to look different to what you expect and not be on brand with your site.
To fix this you can use a free online tool that will strip away any styling and unnecessary HTML.
Go to: https://html-cleaner.com/
Paste your text in the highlighted field.
Select the options you want to process. Keep this as default if you are not sure.
Click Clean HTML button.
You can now copy the text on the left hand side again and paste it in to your site. This will have removed any extra HTML that may be breaking your styling.