I have made a test website, so it will be clear if this is the feature suits you.
Whatsapp button on MY ORDERS page.
https://luckymart.ml
If you are wondering why I don't put detailed order with list of items in the whatsapp message, most likely store owner will ignore the app and process the order with information from the whatsapp message. This will make a lot of unprocessed orders.
It's better to send Whatsapp notification to store owner with order summary, so the store owner will be forced to open app and accept order to see the item list.
I recommend to test it using your mobile phone, cause it needs to open whatsapp application.
If you must test it on your computer, please resize your browser window to look like a mobile screen, refresh your browser after resize.
Full screen computer web browser will not work.
Simple modifications (adding more emojis or change text) are FREE.
You will get the compiled NodeJS (/static folder) files.
You can contact me by ordering a food on the website above!