If your form asks users for private information like their phone number, they may question why it's needed. Users may also need more details when performing tasks like creating a new password. Here, using a helper text — a quick note below the input field — clarifies your intentions or requirements. Make sure the helper text is informative and briefly explains what information users are expected to enter or why the system needs this information in the first place.

When there's a validation error, the error message usually replaces the helper text. Once the error is resolved, the helper text can return.