The "options" and "add-ons" you see in the specific product setup are ones that only you can choose on your end when building a client's quote or order. These internal choices are not available for the client to opt into on their quote.
To make add-ons selectable by the client, you'll want to create a separate product in Settings › Products that can then be added to your quotes as an "optional" item for the client to upgrade their order. They can choose the quantity of these optional items before adding them to the order at that time as well.
For more on Quotes, see our Help Center article that covers both standard and advanced quotes: