Use a text area when the user needs to enter more than a single line of text, such as:
answering an open-ended question
writing comments or descriptions in a form
Do:
use a text area for multi-line input
include a clear, visible label describing what the user should enter
show the character limit if there is one
let users know how many characters they have left (if this is relevant and possible)
Avoid:
using a text area for short, single-line input – instead use a text box
using placeholder text because it may not work with assistive technologies, can fail colour contrast checks, and might be mistaken for pre-filled content