GST E-Invoice Date

Back dated E Invoices we can Generated Only when E way bill Not Required e.g. in service industries otherwise E invoice Required in same day because during transportation of Goods invoice ( e-invoice now ) & E way bill needed 

The process would be same. There is only one consequence for this, if you have already filed your GSTR-1 then while auto-populating E-invoice data to GSTR-1 the comment for such invoices would be “GSTR-1 already filed so auto-population is failed”