In plain language
For legal, financial, or data-changing submissions: user must be able to review, correct, confirm — or undo.
Who it affects
Everyone in legal, financial, or data-changing flows — especially people prone to input mistakes.
How to check
Walk the checkout/signup/delete flows: look for a review step, editable summary, confirmation, or a reversal window. Worked example — A professional networking site's profile editor: reach the review page in a submission flow and try to edit an entry: if the fields aren't actually editable, it fails the 'correct before submit' requirement.
Common misconception
This rule only applies to legal, financial, or data-deletion actions, not every form. But teams often either over-apply it everywhere or, more commonly, skip the review step on exactly the transactions that need it most. Real example: on an e-book reader's library page, deleting a saved book from the library page removes it immediately and permanently with a single tap — no confirmation step, undo option, or review-before-submit stage.