Create a web page

I'm looking for a simplified one page checkout webpage. i.e. I want customers to go from product selection to order confirmation on the one page. There is only one virtual product measured by area in m² so I want the number of 'units' (m²) to be calculated once the customer has drawn a polygon on an online map all within the same page. When the order is confirmed I want to receive the following in the order: The polygon's coordinates The area in m² The dollar amount The name of the person The email address of the person The business name of the person (optional) When the order is confirmed I want the customer to receive the following in the emailed receipt: An image of their polygon area The area in m² The dollar amount The name of the person To date the website has been drafted using WordPress with the X Theme, WooCommerce and the WooCommerce One Page Checkout and WooCommerce Checkout Field Editor Pro extensions. But I am happy to consider alternatives. My payment gateway preference is Stripe. I've done some background work on the mapping and polygon area calculation using a Leaflet map and some Javascipt. So you would be able to use that if you wish or do it yourself if you prefer. I should say that my attempts to combine the map and a checkout process have stalled but I'm a novice in web dev and programming. My preference is for an approach that allows for clear and simple changes in future, with good version control practices, and flexibility for device use (PC, mobile, etc). My preference is to establish an ongoing relationship based on the performance of this project. Performance would be measured by the quality of webpage developed, the quality of communication to get there, and the price.