A registered person supplying taxable goods shall, before or at the time of,—
(a) removal of goods for supply to the recipient, where the supply involves
movement of goods; or
(b) delivery of goods or making available thereof to the recipient, in any other
case,
In case of Service As per Section 13 of CGST Act : The time of supply of services is earlier of following
1.Date of ssue of Invoice 2. if invoice is not issued within prescribe time or date of receipt of payment whichever is earlier 3. Recepient show recepit of services in his books of Account (when 1 & 2 not applicable)