Thanks for contacting Syncfusion Support.
You can achieve your requirement by using “FormatString” property which determines the format specifier by which the display text has to be formatted. By default, we can maintain three types FormatString (n, p, c). Please visit the user documentation for more informationUG Link
By passing your own symbol (lbs, Bmp and any other symbol) as string, we can add that with SfNumericTextBox value. Please use the following code ExampleCode Example
|<NumericTextBox:SfNumericTextBox x:Name="sfNumericTextBox" Value="200" FormatString="₡"/> |
We have created a sample for achieving your requirement. Please download the same from the following link