HTML Embed

When HTML embed plugin is enabled for your text format and its icon added to the toolbar, you can click the icon to add a secondary editing area that accepts HTML code:

Enter the HTML snippet and confirm by clicking the green check mark on the right side. After that, depending on the plugin’s configuration, the secondary window can show the code itself,

or the rendered preview:

In each case there is an edit icon in the upper right corner of the secondary window that allows further edits of the HTML code.