GSTR-2B is an auto-drafted ITC statement which will be generated for every registered person on the basis of the information furnished by his suppliers in their respective GSTR-1, 5 (non-resident taxable person) and 6 (input service distributor). It is a static statement and will be made available for each month, on the 12th day of the succeeding month.
Source Taxguru
Also Taxguru – ‘Matching Offline Tool’ for matching GSTR 2B with purchase register- FAQs & User Manual
