Go to Policies under IAM Dashboard
Select Create Policy

Select a Service

Example: Already exising - IAM user
Nb: You can create your own permission using policy editor.
Nb: Ther are two types of policy editor.. Visual and JSON
You can use visual and then select an already existing like IAM user above
or
You can use JSON and write your own script.

Eg: For a script on Permission to only allow someone create a user, add list users and delete users…… You can add a statement or ask ChatGPT to… (Generate an AWS IAM policy to create, add list users, and delete users) Copy the ChatGPT search result, go back to AWS
Select JSON and paste ChatGT code then Select Next

Name the Policy… eg: Create-User-Only
Description: This policy alows you to create, list dd and delete users only
Select Create Policy
Nb: You can attach the newly created Permission/Policy to a group