Suppliers are required to ship your items in brand-neutral packaging without any promotional materials from their own company.
However, please note that certain items such as clothing may come with the manufacturer's tags. The tags are used to signify that the items are new and unused. They are also used to honor refund policies set by the suppliers.
Some suppliers may also be the original manufacturer of their own brands, therefore their logos may exist on the product itself. In these instances, you should be able to see the supplier's logo on the product listings' photos or the product listings' disclaimers.
Example below:
