Build an Online Store - Addition to existing site

I am looking to add a page to my existing website which is built on WordPress. It's a simple one page store, with only 1 product - "Tax Preparation for $99" - I want users to be able to purchase online and pay via paypal or credit card. I also want a plugin that will act as a client portal, where users create accounts and are able to share their files with me and i can upload final documents to them. Also, when the purchase is complete, I want the clients to enter their information on a form, I will provide the info required for you to add to the form. I have done some research and WooCommerce seems like an easy tool for creating an online store, just need the client portal to integrate well. When responding with your quote, please include any recommendations for plugins for client portals and if you have experience building this before. I want a simple, modern, page with easy to use portal for both clients and myself.