Due date for GSTR3B, GSTR1, & GSTR4(COMPOSITION)

Government has extended dates for GST filings via notification No. 52/2020 dt 24.06.2020.

You can download notification via this link:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.cbic.gov.in/resources//htdocs-cbec/gst/notfctn-52-central-tax-english-2020.pdf&ved=2ahUKEwj1lbz1qvXqAhXbX30KHelyDmsQFjADegQIAhAC&usg=AOvVaw1FX-KGCNRHNul7SuvwWGw5

For F.Y 2019-20 GSTR 4 (Composition scheme) date extended to 31st August 2020.

For extended Due date of GSTR 1 and GSTR 3B you can refer attached file.

Due date for June:
GSTR-1: 11th July, 2020
GSTR-3B: 20, 22 and 24 based on turnover and state of registration
GSTR-4: 31st August
Due date for July:
GSTR-1: 11th August, 2020
GSTR-3B: 20, 22 and 24 based on turnover and state of registration
Due date for August:
GSTR-1: 11th September, 2020
GSTR-3B: 3rd October, 2020

GST Compliance Calendar of July 2020 

for GST Notification and Circular you can refer here 
 

@ Bhavika Kothari ji

due date mentioned by you is old due date (before extention)
for new extended due date pls refer attached file to earlier reply.