2. This is a problem with the PDF reader. Just change the reader.

3. Enter the online business registration page. When submitting a PDF form, if you encounter the prompt "There is something wrong with at least one signature", it is because the certificate you signed is not credible. Click the "Signature Properties-Show Signer Certificates-Trust-Add to Trusted Certificates" function that you signed in the PDF document to add all signed certificates to trusted certificates, and then try the operation again.

Why do pdf signatures have to be verified every time?

The signature part, other parts are deducted as transparent and saved as transparent picture formats such as PNG or TIFF.

Open the PDF file with Acrobat, execute the menu "Advanced/Signature and Verify/Sign Document", and then create your own electronic signature, using that picture as the appearance of the signature.