How to make bundle product is optional

Hi,

These are "option products" not "bundled products". That's another setting.
To make option products optional even when they have variants, you can do as explained here:
www.hikashop.com/forum/product-category-...t-option.html#314031

You can add an entry with the namekey add_no_to_options and the value 1 in the table hikashop_config via your phpmyadmin to add the No value to the option dropdowns.
And you can add an entry with the namekey select_option_default_value and the value 0 in the table hikashop_config via your phpmyadmin if you want that "No" value to be selected by default.