How can I save the custom option value in Magento 2 database?

Question

How can I save this custom value in database and get in the cart page with the custom option ?

Answer 1

I think you should use, catalog_product_type_prepare_full_options event because this event triggered just before the product with its custom options is converted to a quote item.

In this event you can get added product object $product object by using,

$product = $observer->getEvent()->getProduct();

Now you can add your custom option like,

$infoOptions[] = array(
                            'label' => "YOUR_OPTION_LABEL",
                            'value' => "YOUR_OPTION_VALUE",
                        );

you can update this option according your requirement,

Now just add this custom option like,

Add this custom option by

 $product->addCustomOption('additional_options', serialize($infoOptions));