Supporting details are statements which support your topic or theme. You support your main idea by explaining it, describing it, defining it, or otherwise giving information about it. You will usually need to actually look up or research this information!

When you are writing an essay or report, each paragraph after the introduction should discuss one supporting detail. Depending on how many paragraphs you want to include, you can have any number of supporting details.

These details are then repeated or rephrased in your concluding paragraph, to restate the fact that they support your main idea.
give more information about the topic and or details or information that backs up an sentence.