Edit the page you wish to enable the Transparent Header on and scroll down to the "Page Config" tab.
Locate the "Floating Header" section
Note this option should only be used for pages with no sidebar selected.
Select the "Float" option to set the header to "Float" above the content on the page. Note: This option is only recommended if you have a semi-transparent header background.
Float + Transparent
Select the "Float + Transparent" option to set the header to "Float" above the content on the page and set the background of the header to transparent.
Set the Float + Transparent Text Color / Logo
To set the "Float + Transparent" text color and logo, goto Appearance > Themes > Customize > Select the Skin you're using and goto Header > Transparent Header and select the Font Color and Logo version.
Note: This is required if your header is light and the content you're "Floating" the header above is dark.