As per Rule 47 of the CGST Rules, The tax invoice referred in Rule 46 in case of supply of services has to be issued within 30 days date of supply of service.
GST Tip – 286
Notification No. 14/2017-Central Tax (Rate), activities or transactions undertaken by the Central Government or State Government or any local authority in which they are engaged as public authority, shall be treated neither as a supply of goods nor a supply of service, namely:- “Services by way of any activity in relation to a function entrusted to a Panchayat under article 243G of the Constitution.”
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