How can I create a text box with 2 or more rows of size (width, not length)?

Do you mean you want to have unlimited number of textbox for one field? If so, you can try to use the Dynamic Textbox widget. You can check this link for more information: https://widgets.jotform.com/widget/dynamic_textbox. You can also check this sample demo form of the Dynamic Textbox Widget: http://form.jotformpro.com/form/51233651283955?.

If you are referring to a different concern, please provide us more details so we can further check the issue. 

Regards.