You are able to make 2 different edits to your invoices.
You can edit the header and/or the line items.
To edit the header:
Navigate to the invoice. Click Edit to begin editing the invoice information. Click Save Changes when finished.
Please note: You are not able to edit the subtotal. This is calculated.
To edit line items:
Navigate to the invoice. Click the Pencil icon next to any line item. Click Save when finished.