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 disabling slider or changing it with other title types
Example Breadcrumbs or Title, Go to Page Edit > Page Settings > Title Type
For overall website title type go to Theme Options > Title & Bredcrumbs
You can edit icon, text, typography, colors and margins inside of this element edit box in page builder.
You can edit Content Box for styling the box and then edit the Title and Text element for styling and settings of inside text.
Instead Quick Contact also you can create any page and assign it.
In widgets find Footer 1 to Footer 3 sidebar area sections and edit them.
For changing background of Footer, Go to Theme Options > Footer > Footer Widgets > Container Style Kit
For changing the color go to Design Options tab and set your color
For adding background Image (Parallax Image) You can edit row under tab General find Parallax image and add your image.
you can set the hover FX and styling the icons via options and Stylekits there
For changing margin (Position), go to Theme Options > Header > Top of Header > Social
For editing menu navigation settings go to Theme Options > Header > Header > Menu Element
And for styling menus go to Theme Options > Header > Header > Menu Styles of this Row