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# How to create Metafields in Facebook Feed app and sync to Meta commerce manager ?

## Creating metafields in Facebook Feed app and syncing them to Meta commerce manager involves three simple steps

### Step 1 : Creating Metafields Definition

* Go to Shopify settings > Custom Data.
Choose whether the metafield is for **products** or **variants**.

![](https://storage.crisp.chat/users/helpdesk/website/87f7644782da2800/1b39c053-718e-425a-9d3d-24b0d6_1azirgw.png =745xauto)

* Select Product and click "Add Definition"
* Provide a name, namespace, and key. Namespace and key will be used system to identify this definition. For this article, we will take **GTIN** as a metafield example. 
* Add a description and select a **data type** based on the required format. It is **important** to select the correct data type for the metafield to ensure it functions properly. [Refer to the table](https://help.adnabu.com/en/article/what-type-of-values-are-expected-for-specific-attributes-in-metafields-1qh518n) for the appropriate data type for each attribute.

![](https://storage.crisp.chat/users/helpdesk/website/c30d79ee0445c000/52d94616-91f2-49ca-a782-03db56_1ua471w.png =745xauto)

* Once saved, your metafield definition is created.

**Quick Tip :** If the property applies to all product variations, it is advisable to create a product metafield. For unique properties specific to certain variants, opt for a variant metafield. For instance, color would be classified as a product metafield.

### Step 2 : Creating Metafields in Facebook feed app

Navigate to Settings > Product Customization > Metafields and click Add Metafield.

![](https://storage.crisp.chat/users/helpdesk/website/-/e/b/1/4/eb146ac45ce84800/image_yiis8x.png =750x311)

* Choose the appropriate resource based on your metafield definition.
* Enter the metafield **key** and **namespace**. In this example, namespace will be product and key will be GTIN.
* Choose the specific **attribute** from the dropdown menu that you wish to sync with Meta commerce product feed. In this case, the attribute selected will be GTIN.
* Click Submit to add the metafield.

![](https://storage.crisp.chat/users/helpdesk/website/-/e/b/1/4/eb146ac45ce84800/image_18iamvv.png =745xauto)

### Step 3: Adding Values to Metafields

* Go to the product edit page in Shopify.
* Scroll down to the metafields section at the bottom.
* Input the appropriate data in the metafield you created.
* Ensure the data format matches Facebook's requirements. Refer to this table for appropriate format for each attribute.
* Save the product and go back to Facebook feed app.

![](https://storage.crisp.chat/users/helpdesk/website/1b666bc371a3c200/a4e06837-7b3d-40e9-8df0-cc7608_6wnlmi.png =714xauto)

* Update feed to sync your attribute to Meta commerce manager. You can also visit Meta commerce manager to check if attribute is correctly synced.