What should I do if I find that my mobile phone has no card?

Give it to relevant institutions, etc. Check whether there are personal information on the mobile phone, such as contacts, text messages, etc. If you find the owner's contact information, you can try to contact the owner and tell him that you have found the mobile phone and discuss how to return it. If you can't find the owner's contact information, you can give it to the local lost and found office, police station or mobile phone operator.