When you first open a .docx exported from Atticus, it won't include indents, line spacing, etc. However, because of the way the document is set up, you can quickly modify most of these settings in just a few seconds if you need to meet specific requirements for your editor.
Your menus may vary depending on which version of Word you are using.
In the "Home" ribbon you should see a section for Styles (marked by a red box in the image). Since the entire body of your document will be formatted using Normal style, you can right click Normal in this menu > select Modify and you'll see a Style Properties menu pop up.
From this menu you can adjust the font and font size under the Formatting header.
If you'd like to add indents, increase line spacing, modify alignment, or add spacing between paragraphs, click the format button (bottom left of popup) and select Paragraph.
Save all changes by clicking OK on the popups, and the entire body section will be adjusted.
Repeat on Heading 1 if you'd like to modify your chapter titles.