TextEdit is Apple's default text editor-and-word processor-in-one app for Mac OS X 10.3 ("Panther"). A new or opened document can be converted between plain text and rich text via the Format menu, and the user interface will change accordingly. The program has a very simple user interface, it's fast and responsive, yet it's also full of features. Spellings that don't match the dictionary being used will be underlined with a red dotted line, like in MS Word. There is drag and drop support for images and text. TextEdit can open Word, RTF, SimpleText, HTML and plain text files, and it can save in RTF, Word, or plain text formats. Documents can also be printed, saved as PDF, faxed, or spoken by the computer using Apple's built-in Text to Speech (aka "Synthesized Speech") engine.

In rich text mode, the user interface includes a simple toolbar and a ruler that can be hidden. More powerful features are available via the menu bar which has short and well-organized menus (Edit menu is the longest with only 13 items, not counting separators).

When in plain text mode, the user interface loses the toolbar and ruler, and becomes as simple as Notepad's user interface. Unlike Notepad, however, TextEdit supports multiple undo and redo. A plethora of character encodings are supported for open and save. Default encodings for open and save can be specified. One of the more interesting encodings supported is non-lossy ASCII which converts non-ASCII characters to octal or Unicode hexadecimal escapes (great forJava sourcecodes). You still might want to keep a more powerful text editor around on your Mac for more advanced functions. For example, when I was writing a plain text file in UTF-8 encoding for Notepad, I used jEdit to add a byte order mark and to convert line breaks to PC format.

According to Wikipedia, TextEdit was first developed for OpenStep and NEXTSTEP.