Hi @gowtham, the following steps are for adding an issuer.
You need to create your issuer JSON like this
https://issuer.growbit.xyz
take in mind that the image in the JSON is visibile in the Blockcerts app.
The JSON key introductionUrl value should be a public HTTP endpoint.
When the user, on the Blockcerts app, click on Settings and then Add Issuer he need to insert as Issuer Url https://issuer.growbit.xyz (the location of issuer JSON) and optionally an OTP.
When the user confirm the Blockcerts app execute an HTTP request to the introductionUrl: in this way your backend can verify the OTP and register the shared Bitcoin address that the App has generated for the tuple user/issuer. The address is inside the JSON HTTP request payload.
Thanks to the OTP your backend can link Blockcerts app Bitcoin shared address and the identity of the user.
The next step is to build the certificate JSON and create a link as @downie explain.
Have fun!