Shipping can be added to invoices, bills and estimates both on a per-item basis and to your statement subtotal. We'll go into both options now:
Adding shipping to line items:
In order to add a shipping to a single line item, click the shipping button located in the righthand corner below your line item name and description field. After clicking on this button a popover menu will appear, allowing you to either use a saved shipping or to add a new one. If you're adding a new one, please enter a shipping name and its rate. Your shipping rate must be a fixed amount (e.g. "10.00"). Clicking on remember will save this shipping for reuse.
Adding total shipping:
Shipping can also be applied to your statement subtotal. In order to add a total shipping, click on the shipping button below your statement's "Balance" line. This will add your total shipping as a separate line, also allowing you to specify a shipping name and rate. Clicking on remember will save this shipping for reuse.
Default total shipping:
By navigating to Business Settings > Taxes, Discounts & Shipping you'll be able to see all shipping items currently saved in your account. By checking the "Set Default?" checkbox next to any one shipping, you make sure to have invoicely add this shipping to all future invoices, estimates and bills by default.