If you want to sell some service offering online, you need to create a corresponding service plan first.
Note:
1) When creating a service plan, you will need a service template and several other objects. A number of objects are available out of the box. However, if in the process of service plan creation you will need to create your own such objects, go to Creating Your Own Set of Service Plan Related Objects (Optional). Then start the process of service plan creation from the beginning.
2) You can create service plans only for those services which were properly deployed and configured in your system. If in the process of service plan creation you find to the contrary, deploy and configure the service you need as described in the respective documentation. For more information see Creating and Managing Service Offers (Sales & Product Management).
To create a service plan: