GST CAMP 08

Last date of filing CMP08 of last quarter 2019-20= 7th July 2020. First quarter of filing CMP08 for 2020-21=18th July 2020.

Yes, The due date for FORM GST CMP-08 (Challan cum Statement) For the Q4 (Jan 2020 to March 2020) of F.Y 2019-21 was 07th July, 2020 (07/07/2020)....
and for the Q1 (April - June 2020) of F.Y 2020-21 was "18th July 2020 (18/07/2020)."... already passed.

Sir,
is the date extended of filing return?

GSTR 4 Annual return for Composition dealer for F.Y 2019-20 last date is 31st August, 2020

is it mandatory to give the inward supplies in gstr 4

It's not mandatory as per the notification issued earlier at time of Quarterly filing of GSTR 4.

but now, GSTR 4 made annually and for annual return there is no separate clarification/exemption till date.

So it's advisable/mandatory to disclose the Purchase details in your Annual FORM GSTR-4 for F.Y 2019-20.

Due date of quarter ending March 2020 was 7th July and for quarter ending June 2020 was 18th July