You can use a text area instead of a text box. It's the button right next to the text box. Select the text area and click on an empty cell. Then drag an attribute from the connector to the text area to connect the text area with an attribute from the object of the dataview.
You can use the Text area widget for this. This also lets you specify the number of lines the textbox has.
You can find it in the top bar when editing a form.