A textbox role is assigned to the element which allows the user to type some text into the field. Usually this will be achieved using input type=”text” in normal HTML semantics. If this information is not intimated to the user in a different way and screen readers do not recognize the textbox role can be used.
Usually a textbox provides a possibility to have a single line of text and on hitting enter the form gets submitted. To have more lines of text input type=”textarea” is used. The same can be achieved with multiline property of ARIA. Set ARIA-multiline to true.