To register as a seller on AliExpress, you need to follow the steps below:

1. Open the AliExpress website and click "Seller Registration".

2. Select the type of seller you want to register. AliExpress provides two types of sellers: individual sellers and corporate sellers. You need to choose according to your situation.

3. Log in to your Alibaba account and fill in basic information. If you already have an Alibaba account, you can use it to log in to AliExpress directly. If you don't have an account, you need to register an Alibaba account first. When filling in basic information, you need to provide information such as company name, contact name, contact number, company address, etc.

4. Submit certificate information. Depending on the type of seller you choose, you need to provide different certificate information. For example, individual sellers need to provide proof of identity, personal bank account information, etc., and corporate sellers need to provide industrial and commercial business licenses, organization code certificates, etc.

5. Wait for review. After submitting the information, you need to wait for AliExpress to review it. The review time is generally 3-5 working days. After the review is passed, you can start selling products on AliExpress.

It should be noted that sellers registered on AliExpress need to provide real and valid information and certificate information. In addition, in order to improve the reputation and sales effect of the store, it is also necessary to improve the store information, publish high-quality products, provide good customer service, etc.