To join Shopee's authentic guarantee, you first need to become a Shopee partner. Then, you need to provide relevant supporting materials, such as supplier cooperation agreement, product authorization certificate, etc., to prove that the goods you sell are authentic.

Next, you need to comply with Shopee's regulations, such as providing true product information, timely delivery, etc.

Finally, Shopee will review and monitor your products to ensure the quality and authenticity of the products, thereby providing consumers with authentic guarantees.