The "Partners & Services offered" feature facilitate configuring the following add-on-s to products that are already added to the database (Learn how to add a product here)
The key point is that only a partner can offer a service. If you have not associated to any partners for any of these services and you do it in house, you can add yourself as a partner.
To offer a service, a plan need to be created on behalf of the partner. Learn about plans here