How to make a parallax effect with Visual Composer?
1. Click on the "Edit row" icon where you want your background image appear.
2. Activate the parallax option.
3. Select the "Design Options" tab.
4. Insert a background image.
5. Then create a row INTO this parent's row.
6. Add your content into it. The parallax will be applied in the parent's row and the child row will have the parallax effect.