Control Template
RadNumericInput's visual appearance is defined through a Control Template. In order to customize the way the NumericInput looks, you would need to take the default ControlTemplate and modify it.
This topic gives an overview of the ControlTemplate of the NumericInput control, so you can copy it to your app and make changes. The template consists of decrease and increase buttons, the entry control for entering values as well as the accompanying styles.
The original ControlTemplate
The XAML defined below relies on the following namespaces to be set:
You need to copy the original ControlTemplate and its resource dependencies to the Resources section of the page, then you can modify the used colors, sizes, relocate or remove elements (for example you can align the two buttons after the entry).
Any ControlTemplate element that is prefixed with "PART_" is almost always a required part. Removing such a part will result in the control not working. For example the NumericInputEntry control is named PART_Entry and cannot be removed.
Finally, use the custom ControlTemplate as a StaticResource on any instance of RadNumericInput: