The declaration process when buying goods on eBay mainly involves customs duties. When domestic users buy second-hand items on eBay, they may need to pay customs duties. This depends on the value and type of the purchased items and whether they are imported goods. However, the specific declaration process and required materials may vary depending on different situations. It is recommended that you consult the relevant customs or tax authorities when purchasing, or directly search for relevant help information on eBay for more detailed guidance.