WP marketplace for selling custom PDFs

We are looking to create a wordpress site where different designers can sell their invitation designs by uploading their designs and selecting prices. And visitors can choose which design they like and customize it by entering few fields of text. Once they finish entering text and paying they will get a PDF with the design they choose and text entered into right places. Also, they should have an option to mass email this pdf to friends, using an SMTP mass emailing service. Bonus: If the same friends can get an email again in a few days/weeks with a reminder about the event. Bonus++:If the same can be sent out to whatsapp. If you know of any Wordpress templates that are built for this please give suggestions and ill pick something.