Textareas allow users to enter multiple lines of free-form text or data input.
Usage
When to use
Text areas are commonly used in forms to collect user feedback and comments. Where applicable, turn on the character limit counter so users know how much text they can enter.
Required vs optional
You only need to indicate either the required or the optional field, depending on which appears less frequently in the form. Having too many words in a label will increase complexity and lower readability. The pattern should be applied consistently on the same page, and across the same types of forms in your product.
Hint text
Provide hint text to inform users on how or what data to enter into the field, or to explain additional information. For example, use hint text to inform users how the collected data will be used.
Placeholder text
Placeholder text is supplementary to the hint text and provides additional guidance to help avoid errors. Use it sparingly and where it really adds value. Don't use it if you're merely repeating the text area label. Also don't use it to offer critical information, because placeholders disappear once users start entering data. Placeholder text are less accessible as it can't reliably be read by screen readers.
How best to use
Don't
Don't only label the field in the placeholder. Properly label the field so that screen readers can perceive the text.