Along with plaintext and Markdown, you can also format text on WriteFreely with HTML. Here is the supported HTML you can use in your posts.
<h1>Header</h1>
<h2>Header</h2>
<h3>Header</h3>
<h4>Header</h4>
<p>Text</p>
<ul>
<li>List Item 1</li>
<li>List Item 2</li>
<li>List Item 3</li>
</ul>
<ol>
<li>List Item</li>
<li>List Item</li>
<li>List Item</li>
</ol>
<blockquote>This is a blockquote.</blockquote>
Text
This is a blockquote.
<strong>Bold</strong>
<em>Italics</em>
<u>Underline</u>
<span style="color:red">Style</span>
<a href="https://write.as">Link</a>
Bold
Italics
Underline
Style
This paragraph is also inside the box...
<video src="https://cdn.glitch.com/db7ab5d8-dd97-466b-8180-676147e8fc40%2FUsing%20Write.as%20Themes.mp4?" controls></video>
<iframe width="560" height="315" src="https://www.youtube.com/embed/HJT8yYf-XPs" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
<audio src="https://cdn.glitch.com/db7ab5d8-dd97-466b-8180-676147e8fc40%2F%2333%20-%20Reflection%2014%20about.mp3" controls></audio>
<img src="https://i.snap.as/2HKPL0c.png" />