The Rich Text Editor (RTE) was the standard WYSIWYG editor for TYPO3 for a long time. With Version 4.0 this has changed and HTMLArea RTE is now included.
HTMLArea is one of the best open-source rich-text editors. With it you can set up content from a browser in a WYSIWYG environment, which is then stored in HTML format. But this new editor is anything but popular in the TYPO3 community. For one thing, it often needs to be reconfigured after an update. This isn't usually a huge problem, but with HTMLArea RTE one often has to experiment with TSConfig to get it done. So if you are planning to make HTMLArea your editor you absolutely have to look around the appropriate forums to check whether there are any serious implications for you. http://www.typo3.net/ would be a good place to start.
As we have mentioned, the installation of HTMLArea is easy for TYPO3 4.0 users. If you are using an older TYPO3 version, you can install HTMLArea. Uninstall the old version of RTE; subsequently...