Before you can start creating a template, be sure to add all of your services to the list of items. It takes a few simple steps, check out how it's done here.
Once you've got those added, go to the Invoice Templates tab and open up New Template. Here is where you can build a specific invoice that would be available to send out every time the same type of service/session is booked.
Fill out the text fields in regards to the package you offer. You'll find all of your items in the drop-down menu under the Item Name field. You can add as many as needed by selecting the Add another item button.
Your invoice can be edited or deleted at any time. You can also set the tax rate by clicking on the three dots next to invoice item.
Hit Save and you're done! Your new invoice templates will be available when creating/editing a project or booking with your client under the Saved Templates button at the top of the invoice.