My Mitsu, is a webservice in Japan, allows users to create an estimation(calculation) form. A powerful form allows you to create a conditional form with calculation, and outputs a PDF file. It is suited for business persons. https://my-mitsu.com/ (written in Japanese.) This plugin allows you to output an iframe html tag which displays a my mitsu form in your website’s widge area. Note * In order to create an estimation form, you need to register My Mitsu https://my-mitsu.jp/register . Filter Sample This plugin allows you to set your default values for URL, ID, width, and height. You can alter them by hooking the “mymitsu_widget_default_***” filter. Here is a sample code. add_filter( 'mymitsu_widget_default_width', 'my_widget_default_width' ); function my_widget_default_width() { return 400; }