Change input style with custom CSS

You can use this CSS codes.

.form-textbox, .form-dropdown, .form-textarea {

    background: #fff !important;

    border: 1px solid #fff !important;

    color: #000 !important;

}

Guide: https://www.jotform.com/help/117-How-to-Inject-Custom-CSS-Codes (paste it into the bottom section)

You can also change this in the form designer when you click one of your textbox field.

Example:

Note that textbox and dropdown have different style settings so you have to edit them both if you want them to have the same styles.