At the end of the automation, you can edit the email and select the blue link “Add a variable” to add information to the email as needed.
Most likely you will want to add the code for the Fulfillments. If you do a search in the variables for Fulfillments you will get a bunch of different variables you can use, as well as the quantities to fulfill.
For example, you can add the order number like this:
Order: {{order.name}}
Here is an example that will list the line items of the order:
{% for fulfillments_item in order.fulfillments %}
{% for fulfillmentLineItems_item in fulfillments_item.fulfillmentLineItems %}
{{fulfillmentLineItems_item.lineItem.name}}
{% endfor %}
{% endfor %}
This may or may not be exactly what you are looking for, but you can experiment with almost any aspect of an order and present it in the email.