iA Writer exports .docx files that are compatible with Microsoft Word 2007 or newer, Apple Pages, and Google Docs.

Most supported Markdown features are exported to Word.

Markdown Word
Headings 1–6 +
Unordered Lists +
Ordered Lists +
Task Lists Unordered Lists
Definition Lists +
Blockquotes +
Bold +
Italic +
CJK Emphasis +
Strikethrough +
Superscript +
Subscript +
Links +
Local Images +
Web Images -
Footnotes +
Citations Endnotes
Horizontal Rules +
Page Breaks +
Tables +
Code +
Math +

Markdown markup is converted to HTML prior to export to Word. You can also use HTML tags to format text.

Some tags have no equivalent Markdown markup:

HTML Word
<mark></mark> Yellow Highlight

You can use HTML style attribute on paragraph tag to align text:

<p style="text-align: left"></p>
<p style="text-align: right"></p>
<p style="text-align: center"></p>
<p style="text-align: justify"></p>