Answer:
Supporting details provide the information that supports the topic sentence. You can create supporting details with descriptions, examples, reasons, explanations and comparisons.
The details you use to support your topic sentences depends somewhat on the development strategy (persuasive, compare/contrast, narrative, expository, etc.) that you're using. Are you writing a narrative or descriptive essay? Make your paragraphs come alive with details. A persuasive essay? Use plenty of facts and evidence. You may end up combining several types of supporting details.