The Customizer Export/Import plugin allows you to export or import your all WordPress customizer settings from directly within the customizer interface just one click.
1, Install the Customizer Export/Import plugin either via the WordPress plugin directory, or by uploading the files to your server at wp-content/plugins.
2, After activating, the export/import functionality will be available as a separate section within the WordPress customizer. ( Appearance > Customize > Export/Import )
3, Click Export button to export all settings.
4, You can import the exported dat file to another website.