HI SAPask,
If you set the backflush indicator for the materials, then you no need to issue (GI) the material against production order manually (MB1A/MIGO). CO11N/CO15 are used to confirm the production order by operation wise and order wise. The concept of Backflush indicator is, whether you want to do GI manually or system wants to do GI automatically against production order. You can set the backflush indicator for the materials which are used as an required material for other materials in BOM.t may be raw material/ semi finished / finished as per your business requirement.
Thanks