Make e-Mail optional on Woocommerce sign up

Try this code in functions.php. Since it is a requirement in billing, we need to set it as false.

// For billing email - Make them not required
add_filter( 'woocommerce_billing_fields', 'filter_billing_fields', 20, 1 );
function filter_billing_fields( $billing_fields ) {
    // Only on checkout page
    if( ! is_checkout() ) return $billing_fields;

    $billing_fields['billing_email']['required'] = false;
    return $billing_fields;
}