Feature suggestion: Custom Invoice Items and Tax rates

It would be great to be able to create and save “Items” that you can choose from a drop down etc when creating an invoice. The Item AND Unit Price could automatically populate in the invoice and the end user would only have to enter the quantity. It would save so much time not having to type everything in. This could also be useful for the “Subject” field. Each field should be editable once populated. It would also be beneficial for tax rates. This saves time finding the proper tax rate to apply and reduces the risk of errors.