Difference between GSTR3B and GSTR1

Gstr 3B is temporary format GSTR1 is a permanent form

Gstr 3B needs the final figures of transactions( sales and ITC) Gstr 1 needs full details about sales

 

The GSTR 3B is a simple tax return form introduced by the Central Board of Excise and Customs (CBEC) for the month of July and August. ... In the interim, all GST registrants have to file GSTR-3B form. It is must that you have a separate GSTR 3B file for each Goods and Services Tax Identification Number (GSTIN) you have.

GSTR 1 is a monthly return of outward supplies. Essentially, it is a return showing all the sales transactions of a business