If you just created a new Cognito User Pool and you want to add a new user fear not. You can add that user using the cognito interface but you won’t be able to do much with it as the user will need to be verified and change their password.
Register a new user
You can go to the user interface of your Cognito User Pool and add the user there. That’s my preferred way at this stage. If you don’t want that there is a CLI command for this:
aws cognito-idp sign-up --region {your-aws-region} --client-id {your-client-id} --username admin@example.com --password password123
Confirm user registration
Now that your user is there you will need to confirm the registration and remove that annoying “user needs to change password”.
aws cognito-idp admin-set-user-password
--user-pool-id <your-user-pool-id> \
--username <username> \
--password <password> \
--permanent
Authenticate the user and take tokens
Now you can finally authenticate with that user and get some tokens that you can use for calling APIs or whatever else.
aws cognito-idp admin-initiate-auth
--user-pool-id <your-user-pool-id>
--client-id <YOUR_CLIENT_ID>
--auth-flow ADMIN_NO_SRP_AUTH
--auth-parameters USERNAME=YourUserName,PASSWORD="hunter12"