Change Master Page and Theme in SharePoint 2013

Changing a Theme and a Master Page can be done while Selecting and Trying out Themes using the
 the new "Change the Look" option in Site Settings or under Look and Feel in Settings menu.

Lets Look at the Steps -

Select the "Change the Look" in Settings Option.



Here you can find some really good SharePoint Themes which can switch the look of your Office 365 site in minutes. Here is a quick look of the Themes



When you select one of the themes you would find some Interesting Options like you can Change the background Image of the site,select a color Scheme, Select the desired font and a desired Master Page. Once you are done click on “Try it Out” on the top right of the Master Page.



Next click on “Yes, Keep it” to apply this new Look.



Here is the Final Result.