Identity pools are different from user pools. Identity pools actually provide you with the ability to assign permissions to users to access your AWS resources used within the mobile app by using temporary credentials. This access can be granted to both federated users and anonymous guest users. Identity pools support federated access for users that have been authenticated by user pools, OIDC IdPs, SAML IdPs, social IdPs, and developer-authenticated identities. These permissions are assigned through IAM roles and can be mapped to different users to provide different permission sets.
Once a user has authenticated either via a user pool or a social IdP, the token received and managed by Amazon Cognito can then be exchanged for temporary credentials using the identity pools. These credentials can then be used to access the AWS services required when using your mobile app.