AWS Identity and Access Management
User Guide

Managing IAM Policies

IAM gives you the tools to create and manage all types of IAM policies (managed policies and inline policies). To add permissions to an IAM principal entity—that is, an IAM user, group, or role—you create a policy and then attach the policy to the principal entity. You can attach multiple policies to a principal entity, and each policy can contain multiple permissions.

Consult these resources for details: