[Grace Themes]

Hi,

1. To display subcategories
Go to the Appearance -> Editor -> style.css
add below css code at the end of style.css file

#sidebar ul li ul { padding-left: 25px; }

2. To remove the archives and customize the sidebar, you can use widgets
Go to the Appearance -> Widgets -> Sidebar Main -> Add widget

Please check the documentation
https://gracethemes.com/documentation/wide-range/#widgets

3. To change the title of sidebar Category widget
Go to the Appearance -> Widgets -> Sidebar Main -> Add Category Widget

Regards
Grace themes