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 +
Highlight +
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.

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>