> For the complete documentation index, see [llms.txt](https://kb.logicerp.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kb.logicerp.com/logic-erp-learning-hub-tutorials-and-best-practices/user-access/logic-global-admin/sale-return/do-not-allow-blank-challan-no.-in-case-of-sale-return.md).
# Do Not allow Blank Challan No. in case of Sale Return
**YouTube:** [How to Make Challan No Entry Mandatory in Sale Return?](https://www.youtube.com/watch?v=ScaFTuS7flE)
## How to Make Challan No Entry Mandatory in Sale Return?
In this tutorial, we’ll demonstrate how to enable a validation feature in Logic ERP that **prevents saving a Sale Return entry** if the **Challan Number** is left blank. This ensures data accuracy and compliance during return transactions.
***
### **Enable the Setting in Logic Admin**
* Launch **Logic Admin**.
* Navigate to **Global Settings**.
* Go to the **“Sale Return Settings”** section.
* Locate and enable the option labeled: **"Do Not Allow Blank Challan No. in Case of Sale Return"**.
* Click **Save** to apply the changes.
* Restart the software to activate the new setting.
***
### **Implement the Validation During Sale Return Entry**
* Open the **Sale Return Voucher** screen.
* Try to save a return entry **without entering a Challan number**.
> The software will display a prompt:\
> \&#xNAN;**"Please fill in the Challan number."**
***
### **Enter Required Challan Details**
* Navigate to the **“Other Details”** section of the voucher.
* Enter the **Challan Number** and **Challan Date**.
* After filling in the required fields, click **Save**.
> The entry will now be saved successfully.
***
### **Conclusion**
By enabling the **“Do Not Allow Blank Challan No.”** option, Logic ERP ensures all sale return vouchers include mandatory Challan references. This feature helps maintain transaction accuracy and traceability.
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