The form color setting works with forms made by Contact Form 7 plugin. The plugin comes in theme recommendation under plugin installer and assuming you have it activated, you may adjust the color settings of the forms created by the plugin.

• Field Text Color – The form field text color in the form
• Field Background Color – The form background color property
• Field Border Color – the border color of the form fields
• Button Background Color – The buttons ie; submit button background color
• Button Hover Background Color – When you mouse hover the button, the background color of the button is adjusted using this property
• Button Text Color – The text color on the button
• Button Hover Text Color – When you mouse hover the button, the text color is adjusted using this property