In plain language
Every field needs a visible label, and any required format/rules must be stated up front.
Who it affects
Everyone filling forms, especially people with cognitive disabilities and magnifier users.
How to check
Scan each form: every field has a permanent visible label (not just placeholder), required fields are marked, formats are explained before you type. Worked example — A used-car marketplace's listing filter: look at a multi-field construct (day/month/year as three boxes): check whether each individual box has its own accessible name, not just one distant label for the whole group.
Common misconception
Placeholder text that vanishes the moment someone starts typing is not a label. If it's the only identification a field has, the field effectively becomes unlabeled once in use. Real example: on a podcast app's episode list, a multi-part field (like a phone number split into boxes) has no text label at all — visually it 'looks like' a phone field but nothing says so.