Bill of Supply issuance: composition taxpayers must issue prescribed bills with specified particulars and a mandatory composition declaration. Registered persons supplying exempt goods or services, and persons paying tax under the composition scheme, must issue a bill of supply instead of a tax invoice under section 31(3)(c). Rule 49 (read with rule 46) prescribes required particulars: supplier name, address and GSTIN; a unique consecutive serial number; date; recipient details and GSTIN/UIN; HSN or Service Accounting Code; description; value after discount or abatement; and signature or digital signature. Composition taxpayers must state 'Composition Taxable person, not eligible to collect tax on supplier' on the bill.