Welcome to BBEdit, a WYSIWYG editor for BBCode, a commonly used markup language for styling most forum posts.
At the top, there are multiple buttons that you can click to change the style of text, as well as add certain things, like links, images, and even style it using Unicode fonts. You can even enable
[scratchblocks]and
[scratchblocks]and
[/scratchblocks]support, if you are posting this to the Scratch Discussion Forums.