I have filed all GSTR3B RETURNS and paid taxes for each month. Now when i checked my GSTR1 details o

I have filed all GSTR3B RETURNS and paid taxes for each month. Now when i checked my GSTR1 details of previous months some invoices in each month is missing but tax for the same is paid. So please help that how should i add old missing invoices in september months gstr1 is the procedure same for adding old invoices with new ones or is their any column/head to add those missing invoivces..