I have created Apple Development Signing Certificate for my macbook-air device with my developer account email here and when i export the certificate to view details but I found this then, How can I convert it to human readable language or any other better than this to see its content?
A .p12 file uses the PKCS #12 format. This typically contains a certificate and the matching private key. The file nearly always has a password to protect it so that viewing the contents directly just shows apparently random data. If you know the password for the .p12 file there are many tools that let you view the contents. You can try this:
openssl pkcs12 -in appleid.p12 -nodes
which will prompt you for the password.
Keep in mind that you must keep the private key private to protect your security. For the same reason you should keep the .p12 file private as well, so someone cannot attempt to guess the password.
you should keep the .p12 file private as well
Translation: you shouldn't have posted that screenshot. Think carefully before posting security-related things.