To change or edit your business details, you need to start by claiming your listing, if not done yet (This article explains how to do it). Once you have claimed your listing, you can access the Business Centre.
The Business Centre is a page where you can manage your listing. For example, you can update your business details and location, add some images, select a category, add deals or documents. The most successful listings are those with relevant and up-to-date content.
To find the Business Centre, use this link or hover your mouse over the profile picture on top right, and select Business Centre:
You will then be able to update your listing in your Business Centre.
Important: you need to claim your listing before you can access the Business Centre and edit your listing. This article explains how to do it.