Basically you need two components:
a web shop (B2C)
a Google Account (this account must have admin rights to the Google Ads account and Merchant Center)
If you use one of the shop systems for which emarketing provides plugins (Shopware, Shopify, Prestashop, JTL, Plentymarkets, Lightspeed, Magento V1, Magento V2), emarketing will take care of data feed and conversion tracking.
If you do not use a plugin, you will have to set up product data feed and conversion tracking. We can offer you support for this on request.
If you would like to advertise on Facebook, you will also need:
Facebook profile with admin access to Facebook Ads account / Business Manager