“Certify Mailing List” means you are confirming that your mailing list meets all required guidelines for use in a mailing order.
When you certify your list, you are verifying that:
You have permission to use the contacts on the list
The addresses are accurate and properly formatted
The list complies with USPS and marketing regulations (for example, no prohibited or invalid addresses)
This step is important because it helps ensure your mail is processed without delays and reduces the risk of delivery issues or rejected orders.