The client secret, also referred to as the application password, allows your application to exchange an authorization code for an access token
From the Manage section, select App registrations.
Select the application that you created (for example, OIDC Test 1).
In the Manage section, select Certificates and secrets.
Click New client secret.
Provide a description.
Set an expiry date.
Click Add.
Save the client secret for later use in this guide.