Generally, you can check the goods first and then sign them, or even take them back to check the goods slowly after signing them. If you have any questions, contact the seller as soon as possible. The general seller will give you a good answer, because when you receive the goods, your money has not yet entered his account and has not been evaluated, so if the quality of the goods is really problematic or inappropriate, he will give you a refund or exchange goods as long as he makes it clear, and then you can contact the logistics. As for buying valuables or precision goods, you should first take the first signed receipt and return it to him after inspection, or take it back for inspection. Nowadays, sellers usually pay great attention to online word of mouth. If you complain about him, he will lose more, so the seller will return it to you!