You can also use an AWS Identity and Access Management (IAM) user to update the account telephone number and alternate contacts. The IAM user must have administrator access permission and access to the AWS Billing console.
Make sure that the telephone number has the correct international dialing code standard with no additional spaces or special characters. Also, remove any leading zeros after the country code. For example, the United Kingdom country code is +44. Enter the telephone number 07911 123456 as +447911123456 for the United Kingdom.
To update your phone number, complete the following steps: