You can now use the Azure Active Directory (AD) subscription that is included with your Office 365 subscription to customize the sign-in page your users see.
Add company branding to your sign in page and Access Panel pages
If you have a paid subscription to Office 365, Microsoft Dynamics CRM Online, Enterprise Mobility Suite, or other Microsoft services, you have a free subscription to Azure Active Directory. You can use Azure Active Directory to create and manage user and group accounts, and add company branding to your pages. To activate this subscription and access the Microsoft Azure Management Portal, you have to complete a one-time registration process. Afterward, you can access Azure Active Directory from your Microsoft service that uses it. For instructions on how to register your Office 365 subscription see Register your free Azure Active Directory subscription, and see Manage the directory for your Office 365 subscription in Azure for general management instructions.
The following figure shows which parts of the sign-in page can be modified in Azure.
The large illustration and/or its background color
The banner logo
You can also add text to this area
In addition to the sign-in page, you can customize the Access Panel page in Azure.
If you are ready to add branding, explore the customization options in the Azure content set: Add company branding to your Sign-in and Access Panel pages.