AWS Console - Financial Access

The AI-bot's answer is more-or-less correct, however it's worth pointing out this is just creating an IAM user whose name is a string that looks like an email address. It's not actually making an association between the email address and the billing function.

You may also want to add a billing contact in your account, by going to https://console.aws.amazon.com/billing/home#/account and in the Alternate contacts section adding the billing contact's details. This will ensure that they receive the correct notifications from AWS.

To grant a different email address (non-root user) access to billing information and payment management in your AWS account, you can follow these steps:

1. Sign in to the AWS Management Console using your root account credentials.

2. Navigate to the account name in the navigation bar and select "Account".

3. Scroll down to the "IAM User and Role Access to Billing Information" section.

4. Select "Edit" and then activate IAM access to billing information.

5. After enabling IAM access, you can create a new IAM user with the email address you want to grant access to, or use an existing IAM user.

6. Assign the necessary permissions to this IAM user for billing and payment management. This typically involves attaching policies that grant access to billing, cost management, and payment-related actions.

7. The IAM user can then sign in to the AWS Billing and Cost Management console using their credentials.

8. They will be able to access the "Payments" page to view invoices, make payments if needed, and manage payment methods.

Remember that it's crucial to follow security best practices when granting access to sensitive billing information. Only provide the necessary permissions to trusted individuals, and regularly review and update access as needed.

By following these steps, you can allow a non-root user to handle billing tasks such as downloading invoices, making payments, and managing payment methods, while keeping your root account secure for critical account-level operations.
Sources
Find out who can give me billing information access | AWS re:Post
Managing your AWS payments - AWS Billing