Your iPhone's spell-checking feature automatically adds a red underline to any word that doesn't exist in its dictionary. The underline is purely cosmetic, and the feature is intended to be helpful.

Microsoft Word enables you to quickly view typos and other mistakes in a document by flagging the words that contain them with red or green wavy underlines. However, if you are creating a business ...

How to control a hyperlink’s appearance in Microsoft Word Your email has been sent Hyperlinks are a part of our everyday lives—we readily recognize the underlined blue font as a link to related ...