Customization: Adding a custom column that is referenceable across forms

The customization will really depend on the specific page. Usually when you create a new entity record like Sales Order in your scenario from another, there is an action for that. Besides adding the custom field to the specific “source” and “destination” DACs you also need to override the action processing the conversion from the  “source” entity into “destination” entity.

 In case of Opportunities page, that action is part of the below GraphExtension. The action itself is defined in the CRCreateSalesOrder_SOOrderEntry class. The action that you need to override is DoCreateSalesOrder.

I would say you most likely need to complete T200, T210, T220 and T230 to learn how to do this kind of customizations.

        public class CRCreateSalesOrderExt : CRCreateSalesOrder<OpportunityMaint.Discount, OpportunityMaint, CROpportunity>

        {

            #region Initialization
            public static bool IsActive() => IsExtensionActive();
            protected override DocumentMapping GetDocumentMapping()
            {
                return new DocumentMapping(typeof(CROpportunity))
                {
                    QuoteID = typeof(CROpportunity.quoteNoteID)
                };
            }
            #endregion
            #region Events
            public virtual void _(Events.RowSelected<CROpportunity> e)
            {
                CROpportunity row = e.Row as CROpportunity;
                if (row == null) return;
                CRQuote primaryQt = Base.PrimaryQuoteQuery.SelectSingle();
                bool hasProducts = Base.Products.SelectSingle() != null;
                var products = Base.Products.View.SelectMultiBound(new object[] { row }).RowCast<CROpportunityProducts>();
                bool allProductsHasNoInventoryID = products.Any(_ => _.InventoryID == null) && !products.Any(_ => _.InventoryID != null);
                bool hasQuotes = primaryQt != null;
                CreateSalesOrder.SetEnabled(hasProducts && !allProductsHasNoInventoryID && 
     ((!hasQuotes
          || (primaryQt.Status == CRQuoteStatusAttribute.Approved
 || primaryQt.Status == CRQuoteStatusAttribute.Sent
|| primaryQt.Status == CRQuoteStatusAttribute.Accepted
|| primaryQt.Status == CRQuoteStatusAttribute.Draft
                                )
                            )
                        )
                    && (!hasQuotes || primaryQt.QuoteType == CRQuoteTypeAttribute.Distribution)
                    && e.Row.BAccountID != null);
            }
           #endregion



            #region Overrides
            public override CRQuote GetQuoteForWorkflowProcessing()
            {
                return Base.PrimaryQuoteQuery.SelectSingle();

            }
            #endregion
        }