En tu functions podrías agregar esto
function r_sender_email( $email_address ) { return 'yo@dominio.com'; }
function r_sender_name( $email_from ) { return 'Nombre web'; }
add_filter( 'wp_mail_from', 'r_sender_email' ); add_filter( 'wp_mail_from_name', 'r_sender_name' );