Click the "Add Deliverables" drop down to select any deliverables that are yet to be invoiced.

Click "JOB/4 - Administration Job - Design Drawings"

JOB/4 - Administration Job - Design Drawings

Click "JOB/4 - Administration Job - Maintenance Manuals"

JOB/4 - Administration Job - Maintenance Manuals

Click "REQUEST INVOICE" which labels the invoice as completed.

If your Xero integration is enabled, the button will say "APPROVE AND SEND INVOICE" which will send the invoice through to Xero.

Click "SEND INVOICE" to bring up the send dialog and choose your recipients.
The email will use the invoice template defined in Organisation -> Templates.

Enable the "Send Uploaded Documents as Attachments" toggle to include any files that are attached to your deliverables.
Click "Save" to send the invoice.

Enable the "Send Uploaded Documents as Attachments" toggle to include any files that are attached to your deliverables.
Click "Save"

Click "MARK AS INVOICED" to change the label to show that the invoice has been sent to a client.

How to Create an Invoice and Send It