First, click request PO.
Second, fill in all the required field.
Then, click save as draft at the right bottom of the page.
After clicking "save as draft", it should direct to this page.
When you log into the system again and want to review or submit the draft, click the status toggle.
You will find your draft PO.
You can click the pen to edit your PO.
Once you finish editing your PO, you can change the status to pending for approval.