Learn how to manually create an invoice.

1. Go to Transactions > Sales > Create Invoices.
2. Select a customer from the dropdown.
3. On the Items tab, add the item, quantity, and price, if it's not there already.
4. Select any value in the Tax Code field.
   This field will be overwritten when tax is calculated.
5. Click Add.
6. Repeat steps 3 and 4 for all items in the invoice.
7. Click Save.