Official website, Rongxin Logistics Company, is the most accurate place to check the waybill number, because the numbering rules of each company are different. Looking for the company official website, if you don't know, Baidu can, because general logistics companies have their own websites, which are also open for inquiries and orders.
If official website can't find it, he can only call the logistics company to inquire. If you bought it online, you can ask the seller to check it for you.