Site Identity :
Site identity is the first option in Customize area. It having options like Logo, Site Title, Tagline and Site Icon.
Header Image :
It consist option for uploading Header Image and you’ll be able to crop your image once you upload it for a perfect fit.
Background Image :
This option is available to add background image for your site. After uploading image you’ve options like Preset, Image Position, Image Size in this section.
In this you’ve option for your menu like Main Menu and it’s Options, Menu Locations, Menu Options.
All you theme widgets are placed here. You can Add, Reorder and Edit Widgets from here.
From this you have option for adding extra CSS code for your site.
After installing Redux Framework plugin you’ve lot option provided by Redux Plugin in Appearance > Customize.