Create a simple pay form in wordpress and explain how you would proceed

Hello, I need a wordpress developper to create a form to make payments after auction sales. When people buy an item, they go to the website, select the sale, enter their invoice number, add personal info and proceed to payment. When you submit your proposition, it is IMPORTANT that you explain what tools/plugins/gateways you plan on using. Front-end: I need a simple pay form, similar to this: [login to view URL] The difference will be that the amount in euros will be automatically displayed when an element from the drop down list is selected, thus there will be no field for that. The drop down list shows date and name of the sale in european format d/m/Y. All fields and form should have style names or Ids to be easily customizable with css. Back-end: Ideally, I would like to use a gateway such as woocommerce because I will link it to the bank's API and possibly stripe and/or paypal. The user should be able to easily create "Sales" (possibly as a categories) : Date of the sale : Name of the sale The user should be able to easily create "Sale items" (those pages/items will NOT be visible for the front-end users): The user selects a previously created sale. The user fills 2 fields : - Invoice number (Numéro de bordereau) - Amount in euros