If we have mass number of invoices/deliveries then we can’t find IDOC number by going to invoices/deliveries one by one. So I did some research and found two most important tables IDOCREL and SRRELROLES which reduced lot of efforts of mine. We have to follow certain steps, which are explained below –

3. After that we have to select all values of GUID of a role from table SRRELROLES and enter the IDOCREL’s field ROLE_A


Then we have to select all values of ROLE_B from table IDOCREL and enter the values in table SRRELROLES’s field ROLEID


4. Finally you will get IDOC's number.
