Or in your site front page, in the admin bar find Edit Page ( Back-end Editor ) or Edit with WPBakery Page Builder ( Front-end Editor )
For changing size and margin, go to Theme Options > Header > Header > Logo element
For adding or changing social icons or styles go to Theme Options > Header > Social Icons
For disabling slider or changing it with other title type
Example Breadcrumbs or Title, Go to Page Edit > Page Settings > Title Type
For overall website page title type go to Theme Options > Title & Bredcrumbs
Instead Quick Contact also you can create any page and assign it.
This image has Parallax effect, you can find it in Advanced tab of this element.
This image has Parallax effect, you can find it in Free Position Element > Edit Settings > Advanced tab of this element.
This content box has -120px margin from top, you can find and change it from Content Box edit settings > Container Stylekit
These elements are inside the Inner Row and this row has -230px margin from top, you can find it in Inner Row Settings > Design Options tab
You can edit it with ease. just click on each tab you want and then you can find the contain elements, so edit them easily.
For changing the Tabs Title click on Tab Item edit icon.
You can assigned it to all pages in Theme Options > Footer > Footer top bar
For editing menu navigation settings go to Theme Options > Header > Header Bottom Bar > Menu Element
And for styling menus go to Theme Options > Header > Header Bottom Bar > Menu Styles of this Row
