To approve a single invoice:
  1. In Records, Invoices, open the invoice
  2. On the Invoice tab, change the status drop-down from Pending to Approved
  3. Click save and close

To approve multiple invoices: 
  1. From the Records page, click Invoices
  2. Click Approve Invoices
  3. On the Approve Invoices screen, select individual invoices or choose Select All
  4. Select Approved in the Change status to dropdown list
  5. Click Change Status
Note: This option is not available if the Business Rule to Require invoice approval before payment or posting is not marked