Go through the below. Its

Go through the below. Its taken from a very old white paper available on meta link

Typical Sales Order with Automatic Charges: The basic flow for applying Freight or Special Charges to an order starts in the Sales Order form. A user creates an order and enters the lines. When saving the lines, the freight and special charges are automatically applied to the order line based on
the setup done by the customer. Once charges have been applied to the order header and/or line, the user can see the total charges in the total area of the main tab of the Order Header, and a total of charges for each line in the CHARGES column on the Sales Order Lines form, Pricing tab.
In addition a user can view, modify or add manual charges by clicking the ACTION button on the Sales Order form and selecting CHARGES. In the Charges window that pops up, the user will be able to see in detail all applied Freight and Special Charges. If the charge has the OVERRIDE
ALLOWED box checked, then the user can modify the charge.

Entering Costs and converting them to Charges:  Once the user is ready to ship the order, he/she has the ability to key any costs associated with the line  or delivery. When ship confirmation processes (and specifically when the Order Management Interface processes), those costs will be transferred to the order line as price adjustments. And then the conversion of the costs  into charges will be triggered, provided the COST to CHARGE conversion setup has been done. The converted charges will be applied to the line, and then those charges will get invoiced with the order line.

Sales Order with Manual Charges: The flow for adding charges manually is similar to the flow for automatic charges. The user enters the order header and lines. Automatic charges may be applied, depending on how the setup was done. The user can also manually apply any nonautomatic
charges if he or she has appropriate security. To do that, he/she selects the header or line that he/she wants to apply charges to, and using the ACTION button, selects CHARGES. In the Charges window that pops up, the user can go to a blank line and select from a LOV any manual charge that the order or line qualifies for. Security for manual charges is based on the profile option: ‘OM: Charging Privilege’. If the profile is set to None, the user will only have viewing access to charges
and cannot apply manual charges. If set to Full Access, the user can apply manual charges and modify overrideable charges. If set to Unlimited Access, the user can apply manual charges and even modify non-overrideable charges.

Invoicing and taxation:  All charges are invoiced. Line level charges are invoiced with the line they are attached to. Header level charges are invoiced with the first line that is invoiced for that order. Header charges that are added after some lines have been invoiced will be invoiced with the next line that is interfaced to Invoicing. Charges are sent individually to Receivables as invoice header level freight charges, although AR summarizes them into one freight line for the Invoice. Taxes on charges
are not calculated at this time during order entry, even if charges are taxable in the jurisdiction. If it is necessary for charges to be taxed, the user should set the ‘TAX: Invoice Freight as Revenue’ profile option to Yes and also set up a dummy Freight item in Inventory that is taxable and specify it in the ‘TAX: Inventory Item for Freight’ profile option. Then OM’s Invoicing Integration will send the charges to Receivable’s Autoinvoice as Lines with that Inventory Item on them, rather than as Freight. There the charges can be taxed as required and revenue accounting for the charges using AutoAccounting can be done.