When the Consultant submits the Timesheets it can be approved from the Client Portal as shown below.

The Client Timesheet Approver can verify the number of hours submitted by the consultant and match it with the File attachment.

The client can view the timesheet and Approve or Reject it from the Pending Approval(by me) report as shown below.

The Client can also view the previously approved Timesheets in the Approved by me Report as shown below.