Atticus supports subheadings H2-H6, providing you with the flexibility to structure your content with various heading levels. When you're working on the Writing Tab, you can easily select your preferred subheading level by using the dropdown menu located in the toolbar.
If you're importing a document from Word, Atticus will automatically recognize Word styles H2-H6 (note: H1 imports as the Chapter title). You can also adjust the font and text size of your subheadings in your theme settings under Heading Settings.
You can make changes to your theme on the Formatting Tab by clicking the three dots next to the theme name and selecting Edit or Edit as New Theme.
For more details on how to set up or adjust your theme settings, you can refer to this tutorial: Create a Custom Theme. It provides detailed instructions and tips on creating and modifying your theme.