Please anyone guides me to the checkout page modification.
I would like to add Note, Option, Email and Delivery date in the checkout page before submit the order for Magento 2.
It should be also appreared in the order page.
Thank you for all help!
I know there are many extension but I would like to know exactly where to modify if I would like to do it by myself.
I saw many posts to do it but it is not for magento 2.