Hello,
To change the background color:
1. open the form in design view
2. open the property window
3. select the "detail" from the drop-down in the property
window
4. select the "format" tab in the property window
4. change the "Back Color" property to the desired color
(click the ellipses "..." to open the color-picker).
alternatively, you can use the "paint can" icon (alt text
reads "fill/back color" to change the background color.
Regards,
Jorge