When reviewing a software, the screenshot upload option will appear when you select that you're a current user on the first page of questions. Our moderation team uses screenshots to verify reviews, but rest assured these images are never shown on the public site or shared with anyone else.
Since we use screenshots for verification, there are a couple of things that should be included. Our team looks for a username, company name, or other proof of professional use so that our moderators can see the product in use. If necessary, sensitive information can be covered or blurred as long as the screenshot is still useful for verification.