TextEdit is immensely useful for taking notes and creating simple text files. Auto-spell correction, auto-save, and text transformations were also added later on. The capability to read and write Word files was introduced in Mac OSX Panther, while Office Open XML support was added in OS X Leopard 10.5. Several features and improvements were added over time. As Mac OS X evolved to macOS, so did TextEdit. It replaces SimpleText, the old text editor for previous versions of OS X. TextEdit is a lightweight and simple word processor for macOS.