WYSIWYG(What You See is What You Get) Editor is one of the strong features we need to have when we want to have fancy editors like Microsoft Word, Power Point and etc. One of the popular editors available on the web will be CKEditor 5 and Tiny MCE.
CKEditor 5
https://ckeditor.com/ckeditor-5/demo/feature-rich/
TinyMCE
https://www.tiny.cloud/docs/tinymce/6/full-featured-premium-demo/
Naver Smart Editor 2
https://naver.github.io/smarteditor2/
TOAST UI Editor
https://github.com/nhn/tui.editor