TYPO3 v9 and higher

For installations since TYPO3 version 9 LTS, rte_ckeditor is activated by default and ships with a default configuration for editors.

If you installed TYPO3 via composer with “subtree split”, you must install the extension, for example:

composer require typo3/cms-rte-ckeditor:~10.4

See Installing extensions in TYPO3 Explained for more information about installing extensions.