Hi Sidhigiri,
According to the Section 31(3)(b) of CGST Act,
"A registered person may not issue a tax invoice if the value of the goods or services or both supplied is less than two hundred rupees subject to such conditions and in such manner, as may be prescribed"
According to the proviso to Rule 1 of Invoice Rules,
"A registered person may not issue a tax invoice in accordance with the provisions of clause (b) of sub-section (3) of section 31 subject to the following conditions, namely:-
(a) the recipient is not a registered person; and
(b) the recipient does not require such invoice
and shall issue a consolidated tax invoice for such supplies at the close of each day in respect of all such supplies.
Taking the provisions into consideration, I advise that your client can issue a consolidated invoice for all the invoices of value less than Rs. 200 provided that the recipient is either unregistered or doesn't require an invoice.
Thanks
Hardik Lashkari