Hi There,
Reference your enquiry we would like to inform you that we have gone through your requirements but this is not enough for us to get the in depth analysis of what features you exactly need, with this i can conclude that you need a app where all medicines present in your store will be listed and customer can easily search for the required medicine and can pay for that using the inapp payment gateway option and will also receive a receipt a same for the same, and as soon as the order is made you will receive a notification email along with the details of the medicine as well as the delivery location. This is what i visualize from your description, if you provide me further details it will be beneficial.
Thanks
Hemant