Regarding this question, Doudian is a domestic e-commerce platform where users can open stores and sell. If you need to download a store opening certificate, you can follow the steps below:

1. Log in to the merchant backend of Doudian and enter the "Store Settings" page.

2. On the "Store Settings" page, find the "Store Information" option and click to enter.

3. On the "Store Information" page, you can see the "Store Certification" column, click "Download Certification Certificate" to download the store opening certificate.

Note: If your store has not yet passed the certification, you need to complete the certification before you can download the store opening certificate.