Choose Actions > Billing.
Select the client, engagement, or project for which you want to enter a progress bill.
Click Detail Bill Selected.
In the Summary tab, click the More

button to open the Progress Bills dialog.
In the Time & Expense tab, you can right-click and choose Add Progress Entry from the context menu to open this dialog.
In the Progress Bills dialog, enter an engagement, project (if applicable), activity, staff, and amount, and click OK.
The values you entered will be used on the initial billing transaction you create. The billing will be recorded as having occurred for the staff and engagement / activity entered only until the progress bill is finalized. At that point, the billings will be reallocated to the actual WIP transactions entered.
If you will be printing an invoice, click the Compose tab to edit the text that will be displayed on the invoice.
Click Save.