In Office 365, you can use Design Manager to create a custom website design for your business or organization. Design Manager is an advanced site design tool that makes it possible for you to create the design you want using popular web design tools or HTML editors that you're already familiar with. While you can customize your site using the Public Website editor, with the more advanced features of Design Manager, you can create a completely new design.
Where do I find it?
Design Manager is part of the Public Website in Office 365. Just sign in to your website, and go to Settings > Site Settings > Look and Feel > Design Manager.
How do I get started?
Use the steps on the left side of the page to design your website. Depending on your design and your website's requirements, you may not have to perform all of the suggested steps, and you don't necessarily have to perform them in this order.
The first thing you’ll need to do is create a design. You can create your own using the web design tool or HTML editor you’re familiar with to help you create the design or review it when you’re done. When you share your website with external users, they can see your site and work with it just like you can, before you make it public. If you’re an Office 365 Small Business admin, you can learn more aboutsharing with external users.
Also, using Design Manager, you can take the HTML files and Cascading Style Sheets (CSS) from an existing website that already has your brand and turn it into a new look for your Office 365 Public Website. To learn more about using Design Manager to customize your public website see Overview of Design Manager in SharePoint 2013. If you’re already familiar with SharePoint tools for web design, you can learn about the differences between customizing a public website in Office 365 and customizing a publishing site in SharePoint Server 2013.
What is the Public Website?
The Public Website in Office 365 is the professional online presence for your business or organization that you create. It is a SharePoint Online site collection, like the Team Site collection. For more information, see Get started with the Public Website.