Place of supply rules determine GST treatment of software services, shaping export zero rating and reverse charge obligations. Customised development and related activities in software, and temporary transfer or permitting use of intellectual property, are treated as services under GST, while pre-developed off-the-shelf software supplied on media or via encryption keys is goods. As services, place of supply rules apply, affecting export zero-rating, reverse charge application, and ineligibility for composition. Exports qualify as zero-rated where supplier is in India, recipient outside India, place of supply outside India, payment in convertible foreign exchange, and parties are not merely distinct establishments. Reverse charge applies to imports of services regardless of payment currency; registered recipients may claim input tax credit for tax paid on reverse charge.