Collapse or expand parts of a document
When you’re working on a long, complicated document, you can collapse everything except the part you want to focus on. Or, if you think you might be overloading your readers with too much information, you can display summaries and leave it to your readers to open the summary and read the details if they want.
The ability to collapse and expand content in your document is based on its outline level. When you close and reopen a document, the headings will be expanded by default. If you want the document to open with the headings collapsed, follow these steps.
Place your cursor in the heading.
On the Home tab, in the Paragraph group, click the dialog box launcher.
In the Paragraph dialog box, click the checkbox next to Collapsed by default.