Note: All subscription plans Basic and above come with API access. There's no additional fee for using the API, but if you're currently on a Starter subscription, you'll need to upgrade your plan to gain access.
Click Developer API under Reporting to access this page.
Managing your API credentials
It's possible to update your default API username and password on this page. When you make any changes to either username or password, there will be an option to save and update the details.