WYSIWYG is What You See Is What You Get.
Some Markdown editors could render markdown the same time you are editing it (Currently in the Obsidian you could change between two modes, Preview and Edit)
The goal of the developers is to develop such feature in Obsidian.
You could see how this is implemented in markdown editors like Typora (most known WYSIWYG text editor is Word).
The alternative approach is WISIWYM - What You See Is What You Mean (example of it is how html code is structured, or the markdown in the edit mode)