Set your own preference in issuing a Sales Invoice by entering to Settings > System > Sales.
Simplified Tax Invoice: An invoice without customer's information required.
Use Receipt as default layout: Always issue invoice with receipt format (simplified tax invoice).
Item GST in the invoice: Each and every single item in the invoice can set to include / exclude GST in one invoice.
Editable Item: Able to edit the item details or type customise product name when you issue invoice, without creating / changing in product catalogue.
Auto create product: If the product in the invoice has not already created, the item will automatically saved into product catalogue.
Make payment before checkout: You can fill in payment amount of the invoice before save the invoice. (usually business collect cash on the spot when invoice is issued)
Enable discount: You can add discount amount to the invoice
Simply choosing the GST date as you want: When you issue a back-dated invoice, you may want to back-date GST tax date as well.
Show print window automatically: Invoice printing page will pop-up automatically when you save the invoice.
Additional Field: You can have more information that you wanted to be included in the invoice. (Example: other refer document, date, payment...etc)