If your blog post content covers some different areas of the same topic, you may want to give your readers a visual clue that you are done with one sub-topic and moving on to another. You can do this in a couple of ways–topic headings and divider lines. You can use both, of course.
To set a topic heading, just type it in as a separate paragraph and then place the cursor anywhere in the heading text and click the Paragraph button. You can then choose from different paragraphs types including various heading types from Heading 1 (biggest) to Heading 6 (smallest).
You can add a dividing line, like the one above, after the last paragraph of your topic by clicking on the Horizontal Rule icon framed in red below. You can specify the width in pixels or percent, the thickness of the line and whether or not to show a shadow.