Once a work order is complete, you can convert that work order into an invoice for your customer in the Work Orders app.
To invoice multiple work orders, please see our article "Batch Actions - Invoice Multiple Work Orders".

Invoice an Individual Work Order
If you want to invoice only one work order, select it in the Work Order List. When the work order comes up, scroll to the bottom and click the Create Invoice button.

You will then be taken to a new screen to select the preferences for the invoice(s) as shown further below.

Invoice Preferences to Create Invoices

Invoice Date - This will be the date for all created invoices.
Wait before syncing to QuickBooks - If checked, the invoices will not be sent to QuickBooks and remain within Method:CRM.