Query for Creation of Destination DEV, TEST, PREPROD and PROD with OAUTHClientCredentials

[Anurag004]

Hello Experts, 

I have one scenario/requirement to create Destinations for CTMS configuration.
The Destinations TransportManagementService, ContentAssemblyService and CloudIntegration were already created with the help of Service Key from Instances of TransportManagementService, ContentAgentService with Standard Plan and PI with API Plan. The relevant details (URL, Client ID, Client Secret and Token URL) were retrieved from their respective service keys.

We also needed to create the Destinations of Deploy-Service like DEV, TEST, Pre-Prod, and Prod. They are currently configured with the Basic Authentication.

Now the requirement is to change the Authentication type from Basic to OAUTH2ClientCredentials for these destinations.
My Question is if we change the authentication from BASIC to OAUTH2ClientCredentials for these destinations to have more secure authentication, then from which Instances we can retreive the Client URL, Client ID, Client Secret and Token URL Information? 
All the Destinations are created under DEV Subaccount as of now.
And is there any need of subscribing/instance creation in other subaccounts also? 

Any Guidance and Helps are appreciated.

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Thanks and Regards
Anurag
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