Simply follow the link from your notification, review the details, and either approve/reject the invoice.
When you are a hiring manager associated with a Work Order, and invoice approval policies are turned on for your organization, you'll get an email notification to review and approve/reject invoices.
You can click on the link in the email you receive and it will take you directly to the invoice you are approving. Or, if you are logged in to Liquid, you can navigate to Invoices and then view all invoices that are in status 'In Approvals with Me'. Click on an individual invoice, and you will see the details of the invoice.
If there is a difference in the invoice compared to the agreed to Work Order, you'll see a notice of the mismatch, and can scroll toward the bottom of the invoice to see the details on what is different. You are still able to approve an invoice with a Work Order mismatch.
You can then click on 'Reject' if you want the invoice to be kicked back to the vendor, or 'Approve' if you approve the invoice and want it to be sent to additional approvers and/or to be paid.