In order to create manual invoice, please follow the steps mentioned below, 

Note : Muntazim gives you ability to create manual invoice(s) when needed, user can create these invoices for Grade and Student(s) with Non-Periodic & Immediate Fee Type only.
These invoices can be generated for only one time payment. Recurring is not applicable to these invoices.

Go to Fee Management > Fee Payment

3-Click on Manual Invoice 
4-Select School Academic Session
5-Both options are available to create your invoices "For Grade" Or "For Student" select as per requirement.
6-If For Student is selected, then Select enrolled student from list OR If For Grade is selected, then Select required Grade from list. 
7-Select your preferred Due Date, as your manually created invoices will expire after your selected due date. 
8-Add Fee Type from List(Only non-periodic & Immediate Fee Type will display on provided field) 
9-Discount can be added into this invoice from this option. 
10-Once done click on Save.  

11- After Save Manually created Invoice will fall on List All Invoices Screen.