By Brien Posey, SearchExchange.TechTarget.com
When organizations begin using Outlook Web Apps, it's often only a matter of time before someone on the senior management team asks if OWA can be branded with the corporate logo of colors. As long as you have a basic understanding of HTML and Cascading Style Sheets (CSS), Microsoft makes it easy to customize OWA 2013.
This tip focuses on OWA 2013's premium version which supports customization; the light version doesn't support customizations that are based on OWA themes. You should be able to customize older version of OWA in a similar manner, but you have to slightly alter the technique to differences in the file paths. This tip also assumes Exchange is configured using the default installation path.
Creating a theme in OWA 2013
Although you can technically get away with modifying existing OWA themes, it's smarter to build new themes. If you make a mistake when editing a default theme, you could irreparably damage OWA. Here we'll copy a default theme and use it as a starting point for customizing OWA.
Log on to your Client Access Server (CAS) and navigate to:
C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\OWA\<version>\Owa2\resources\Themes
Create a folder with the name of your organization, then copy the contents of the Base folder into that new folder.
To read the full article, go to: SearchExchange.com