The Underline plugin adds functionality to easily apply underline formatting in Obsidian. By using the default hotkey, users can wrap selected text with `<u>` tags or insert an underline wrapper at the cursor position. The plugin also supports undoing underlines when applied text is reselected. Additional formatting options include wrapping text with `<center>` tags, headings, or block references, accessible through dedicated hotkeys. For even more customization, users are encouraged to explore integration with the Text Format plugin for custom wrappers.