Extension add table field method display name for D365FO

 public static class PriceDiscAdmTrans_Extension

{

    [SysClientCacheDataMethodAttribute(true)]  //This attribute will cache your display method.

    public static display Name My_ItemName(PriceDiscAdmTrans _this)

    {

        return InventTable::find(_this.ItemRelation).productDescription('en-us');

    }

}