how can I set the Revolution Slider int header not in content

Hello,

If you want to place a rev slider element in the header, you will have to use the revolution slider shortcode to do it. You can use this function top wrap the shortcode in so it can be rendered by the theme: https://developer.wordpress.org/reference/functions/do_shortcode/
Here is an example of how to use it:

After you create the slider and add it in visual composer on a page, you can see it’s shortcode in text mode in the classic editor (the mce editor): http://screencast.com/t/wGw8sjS5eqLL
After you identify the shortcode and add it to the function, you need to place the whole function containing the shortcode inside the them file corresponding to the header style that you use:
http://screencast.com/t/LNgnFcnGjEtJ

I hope this helps.

Thank you!