Remove Free Shipping option from invoices

Our business does not offer shipping, how can I avoid using shipping options and having them appear on my invoices?

I would suggest activating the Delivery shipping method. This can be a charged service or free, but it is much more applicable to how your services are provided to your customers.

From the main menu, go to store->shipping options. Find "Delivery" in the list and set it to "active". Now when you are creating an invoice and you "calculate shipping and taxes" - you will see the Delivery option. You will even be offered to "discount" the Delivery rate if you wish per invoice.

Your invoices will now look like this: