When you change the outline level of a paragraph in outline view, nothing much really happens: Write merely applies one of the paragraph styles Heading 1 through Heading 9.
What would some bright spark make of this? Correct: You can also define headings by simply assigning text paragraphs to one of the style templates Heading 1 to Heading 9.
If you want to create a new heading, you can also do this without the outline view. Simply type in the heading and select the desired heading style on the ribbon tab Home | group Styles (or from the sidebar) – done.
You can just as easily change the outline level of a heading. If, for example, you position the text cursor in a level 2 heading and apply the Heading 3 style, the heading is downgraded to level 3.
This can be done even faster: By default, the shortcut keys Alt+1 to Alt+3 are defined for the styles Heading 1 to 3, and the shortcut Alt+0 is defined for the style Normal. Thus, you can very quickly create headings, change their levels or demote them to normal text via these key combinations.
Explanation: The outline level is paragraph formatting!
You may now be wondering what styles actually have to do with the outline.
Simply put, the outline level is very common paragraph formatting for Write. If you open the dialog box on the ribbon tab Home | group Paragraph with the group arrow in the bottom right corner, you will find an option called Outline level on the Paragraph tab.
In the styles Heading 1 to Heading 9, this option was set to 1 to 9 accordingly. This is why you can use styles to change the level of headings.
Note: You should not normally change the option Outline level manually in the dialog box on the Paragraph tab. To do so, use the outline view or the aforementioned styles. These methods are more convenient and avoid potential sources of error.