Singapore, officially the Republic of Singapore is a sovereign island country and city-state in maritime Southeast Asia.
Fiscalization wise, it is not a fiscal country, which means there are no laws requiring specific HW or SW to be used for creating, processing transactions and/or issuing receipts to customers.
There is also no direct communication of the transaction data with tax administration but there are, however, certain obligations regarding issuing GST invoices and receipts and also keeping the relevant data in a way that it can be conveniently and properly audited.
VAT (GST) invoices should always be issued to all the GST registered companies. Receipt can be issued instead of a tax invoice to non-GST customers.
Non-compliance with the document retention obligation is a serious matter and can result in severe consequences.