Please help . I need to add class to this button if user is not logged in
<?php echo apply_filters( 'my_order_html', '<button type="submit" class="ADD-CLASS-HERE cfw-primary-btn cfw-next-tab validate" name="my_list_html" id="place_order" formnovalidate="formnovalidate" value="' . esc_attr( $order_button_text ) . '" data-value="' . esc_attr( $order_button_text ) . '"><span class="cfw-button-text">' . esc_html( $order_button_text ) . '</span></button>' ); // @codingStandardsIgnoreLine ?>
woocommerce_order_button_html
etc, you can see it in the edit history. I'd suggest looking up filters and hooks as you may need to use them depending on where the code is located, but it's still a WooCommerce question, you should ask WooCommerce users how to modify a button in a WooCommerce filter.