A Taxable Supply is a supply of goods and services made in Singapore other than an exempt supply. Goods & Services Tax (GST) is chargeable on a taxable supply of goods and services made by a taxable person in the course or furtherance of his business. However, any GST incurred by a taxable person on business purchases used in making taxable supplies can be recovered from the Comptroller of GST.
FAQ : Singapore GST / Taxation & Accounting