I left my bag in the taxi yesterday, but I didn't expect it to be sent back to me later. I really appreciate him. How can I thank him?

Send a thank-you letter. If your bag is very valuable (many times higher than the price of a banner), of course, you should send a banner. Thank-you letters and pennants are best sent to the driver's unit, so that he will be praised by the unit leader and his good character of collecting money can also be passed down as a beautiful talk. If you give it to him directly, it will be difficult for him to give it to the leader again, which will make him look like he is asking for help, right? )