iOS distribution certificate, sign by another developer

Question

My company just built an app for a client who already has an Apple Developer account and had already created their Distribution Certificates. When the cert is downloaded to our

Answer 1

Please ask client to provide you Certificate.p12 that will include the certificate and the private key.

In order to create .p12, go to Keychain Access, select the certificates option in second block in left pane, and then select the certificate you want and right click > Export > Enter the password for p12 > enter Mac password > save at your desired location.

To install at your side, just get that p12 from client, double click to open it, and enter the password which client has entered for p12.

Finally, you are done with getting distribution certificate which is signed at clients place.