> 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-installation-configuration-and-troubleshooting-solutions/faqs/printing/define-expression-fields-in-printing.md).

# Define Expression Fields in Printing?

**YouTube:** [How to Define Expression Fields in Document Printing?](https://www.youtube.com/watch?v=3V3yjx4_fVU)

## How to Define Expression Fields in Document Printing?

In this tutorial, we’ll learn how to **design and use expressions** in the Designer Printing Format of Logic ERP.

***

### Steps to Create Expressions

* From the **Menu Bar**, go to **Continuous Printing → Sales Bill Print Designer and Printing**.
* Select the **required configuration** and sales bill, then click **Refresh**.
* Open the **Design Window**.

<figure><img src="/files/e5AkLtPVHk60Ezbb6KRk" alt=""><figcaption></figcaption></figure>

* Go to the **Properties Menu** (bottom left) and open the **Expression Designer**.

<figure><img src="/files/BjuiISLezBJmlsiaKvrY" alt=""><figcaption></figcaption></figure>

***

### Building Custom Expressions

#### Example 1: Sum Function

* Click on the **SUM function**.
* Browse and select the required fields.
* The system will calculate their total automatically.
* Use the **equals (=) symbol** to check the result instantly.

<figure><img src="/files/Qusd321PJ9mGi2J7zN7s" alt=""><figcaption></figcaption></figure>

#### Example 2: Convert Number to Words

* Select **Footer Details → Total Net Amount**.
* Insert this field into the designer.
* Apply the conversion function.
* Using the equals (=) symbol, you’ll see the amount displayed in words.

<figure><img src="/files/7yeXSPrQvthvfNmO1rHw" alt=""><figcaption></figcaption></figure>

***

### Saving and Using the Expression

* Once your expression is complete, click **OK** to exit the Expression Designer.
* Click on the **Save Expression** button.
* Give your expression a **suitable name** (e.g., *Amount in Words*).

<figure><img src="/files/8WxZ0DsUsbIplvwg3WXV" alt=""><figcaption></figcaption></figure>

* The new expression will now appear under the **Expression Table** in the Properties menu.
* Right-click on it → **Insert** into the printing layout.

<figure><img src="/files/Qt9ZvAR3m9IEkowKLtH3" alt=""><figcaption></figcaption></figure>

* Save the changes.

***

### Preview

* Go to **Print Preview**.
* You’ll see the new expression (e.g., Amount in Words) correctly displayed in the bill format.

<figure><img src="/files/CbNUk4LeEZ4s3yF8qAKO" alt=""><figcaption></figcaption></figure>


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