To change the icons in Section 3 'Our Features'
- First upload image/icon from Media Library. Go to Media -> Add New
- Copy full path of uploaded image
- Go to Appearance -> Theme Options -> Sections -> Section 3
- Add image URL in image="" in below shortcode
[servicesbox color="#ffffff" bgcolor="#ba950b" image="http://yoursite.com/wp-content/themes/buildup-pro/images/services-icon-1.png" title="Planning & Designing" description="Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur."]