To do this task
Go to the Lists menu and click Item List.
Click the Item button at the bottom of the list and then click New.
Click the Type drop-down arrow and then click Other Charge.
In the Item Name/Number field, enter Markup.
In the Amount or % field, enter the percentage you typically charge for
markup on an invoice. You can edit this rate when creating individual invoices,
so just consider this a default markup rate.
Click the Account drop-down arrow and then click an income account.
Click OK to create the new item.