How would you insert a section break in a document?

This question is not specific enough.  There is no mention of what kind of document.  If the document is a Microsoft word document, then this can be done on the page layout tab, in the page setup group and click breaks all after selecting the point in the document where you want to put the break

If you’re mining for diamonds, you might want to keep strip mining. I’m attaching an image with one of the best strategies I know.