Use helper / info text to add constraints.

- Field label: Password
Helper text: Minimum 8 characters, letters and numbers only - Field label: Upload files
Helper text: Supported formats: PDF, DOCX, XLSX (max 10 MB) - Field label: Phone number
Helper text: Include country code, e.g. +49 30 1234567
- Field label: Password
Helper text: Pick a password. - Field label: Upload files
Helper text: Only upload supported files. - Field label: Phone number
Helper text: Type your phone number here.
Add helper text to build trust and improve the chances of a successful input field completion.
- Field label: Create password
Helper text: Minimum 8 characters, 1 uppercase letter (A-Z), 1 special character (!@#$%^&*) - Field label: Device name
Helper text: Maximum 50 characters - Field label: Max threshold
Helper text: Use decimal point for precision (e.g. 15.5).
Use clear helper texts, instead of placeholders, in high-friction and error-prone fields requiring numbers and specific formats.

- Format: YYYY/MM/DD
- Enter a value between 1 and 9999.
- Enter a future date.
Dos and Don'ts
- Do add helper text to high-risk and error-prone fields
- Do use tooltips instead if more detailed information is needed
- Don't use the same text label wording as helper text
- Don't use helper text when there are extensive requirements, instead use a tooltip