If you want to know whether a real estate certificate is mortgaged in a bank or provident fund center, you can take the following steps:

1. Prepare relevant documents: the owner of the real estate certificate The real estate certificate should be found so that you can view the details on the certificate.

2. Bank inquiry: You can contact the bank that holds the real estate certificate, provide them with the certificate number or other necessary information, and inquire whether there is a mortgage registration.

3. Provident Fund Center Inquiry: If you suspect that the mortgage is at a Provident Fund Center, you can contact the local Provident Fund Center to provide relevant certificate information and ask whether there is a mortgage registration.

4. Real estate registration book inquiry: In China, the real estate registration book is a legal document that saves all real estate mortgage and transfer information. You can check the real estate register through the real estate registration agency for mortgage information.

Please note that the above methods are only preliminary inquiries. If you need exact information, it is best to consult a professional real estate lawyer or consulting agency. They can help you understand the mortgage situation of the real estate certificate in more detail.