Image file attachment to Order Items

I want to modify product page to have an optional 'upload file' field which will be added to cart and to order.

How would I go about doing this?

Thank you

You would need to modify your product page, inserting a file field.
Then modify lib_cart which carries the data during the session.
Then modify checkout_summary.inc.php which builds the order.
Then modify ent_order.inc.php which is the order object.

https://wiki.litecart.net/doku.php?id=how_to_create_a_vqmod