The purchase section displays material requests from the students in your class for which you are a class teacher. You can approve/disapprove these requests.
Once you approve a request, it then has to be sent to the admin.
Consider the above image,
The first request is pending, it hasn’t been approved/disapproved yet. You can use the respective icons to make a decision.
The second request has been approved but it hasn’t been forwarded to the admin yet. To do so, click on the send request icon as displayed in the image.
After the request has been sent you will be able to see it as shown below.
This means the request has been sent to the admin but not issued.
The last request shows a material request which has been approved by you and also issued by the admin. The admin has the ability to refrain from issuing a material for a student.