Hi Rakib,

Thanks for contacting us here. We've got your issue.

I have transferred your ticket to one our developers so that he can check and give you further help. He might need to further discuss with you, so please in touch.

He'll start working on this and will be responding as soon as he's available for support. 

Please stay patient meanwhile cause this might take some time under our current heavy workloads.

Best regards.

Hi Nicola,

Please use this code to control sale text

add_filter( 'woocommerce_sale_flash', 'wooc_custom_replace_sale_text' );
function wooc_custom_replace_sale_text( $html ) {
return str_replace( __( 'Sale!', 'woocommerce' ), __( 'Your Text', 'woocommerce' ), $html );
}

To change background, you need add some small css in custom css in customizer