after_setup_theme | Theme Supports

function alpha_bootstraping (){
    load_theme_textdomain("alpha");
    add_theme_support("post-thumbnails");
    add_theme_support("title-tag");
    $alpha_custom_header_details = array(
    	'header-text'		 => true,
    	'default-text-color' => '#222',
    	'width' 			 => 1200,
    	'height' 			 => 600,
    	'flex-height' 		 => true,
    	'flex-width' 		 => true
    );
    add_theme_support( "custom-header", $alpha_custom_header_details);
    $alpha_custom_logo_defaults = array(
    	"width" => '100',
    	"height"=> '100',
    );
    add_theme_support( "custom-background" );
    add_theme_support( "custom-logo", $alpha_custom_logo_defaults);
    add_theme_support( "header-text");
    register_nav_menu( "topmenu", __("Top Menu", "alpha"));
    register_nav_menu( "footermenu", __("Footermenu Menu", "alpha"));
    add_theme_support( "post-formats", array("video", "audio", "aside", "gallery", "quote"));
}
add_action("after_setup_theme", "alpha_bootstraping");