The Checkbox can be linked with a Product so when the CHECKBOX is selected, an item will be added to the CART alongside the main PRODUCT.
Thank you for your suggestion. Currently, we do have a checkbox element. Even though it can't be included with the product on cart page yet but we still can find it at the Order section on Shopify.
However, would you let me know your main purpose of having checkbox appeared on cart page? Then I can have a better understanding of it.
Looking forward to hearing from you soon!
All the best,
Glad to hear from you. I guess I did not express myself clearly. Actually I wanna add a checkbox on the product page, just under the ADD TO CART button. The checkbox can be linked to a product which is a Gift Box. When the customer select the checkbox and click ADD TO CART button, this product and the product linked with the checkbox(the Gift Box) will be both added to his/her cart.
I find an example. Please kindly check the picture~