Salea Order No in PO Print

Hi Gurus,

I'm a MM Functional Consultant.I'm preparing Functional Spec for PO Print (Smart Form) & GR Smart Form.In both the form Sales Order document no should come as per client requirements.

How to add the Sales Order no in PO and GR by linking table & field name.

Please give me the Table & Field name with Conditions.

Thanks & Regards

PKB