Submit and iOS App for a client that already own an App created by another developer

Question

I've developed an App for a client that already owns an application under his account.

The previous developer has sent a .p12 file to the client with the key for the distribution.

Now I'm a bit confused... what I have to do to submit my app (that is a totally different App, so not an update of their previous App) is relatedi with this p12 file?

My idea is just to create a new distribution certificate using a new CSR and then send my new CSR to the client as backup.

Is this the right way to go?

EDIT: The client has an account of type "company" so I could add myself to their developer account thanks to the tab "People" and I own their username and password.

I just want to know which is the most correct way to do perform a submission for a client.

Answer 1

.p12 has the certificate which are used to create the provisioning profiles. (.p12 file also has the keychain keys )

So you dont have to worry that using .p12 files will update any other apps. Provisioning files are used to sign the apps and based on that you can upload and update any app.

You just need to create a new provisioning profile with the .p12 certificate in dev Center and use it to sign your app and submit.