To add style to a button in your page,

1. Edit your app.
2. Select the required page from the accordion menu on the top-left corner, or from the application preview in the middle. You'll be taken to its  Design  page.
3. Click on the device icon to navigate to the  Design  view of the device of your choice.
   

   

4. Hover in the middle and click  Open Page Builder .
5. Click to select a panel that holds the button you want to customize.
6. Click the  Configure  option in the toolbar in the header area of the page builder. The  Panel configuration  pane slides in.
7. Select  Style  from the configuration options on the right.
8. Choose from the style options:
   
   • Button type : Select the button shape as  rectangular  or  rounded .
   • Change font  for button label: Click the  Font family  dropdown to select a font style.
   • Set text style  for button label: Click the  B ,  I  or  U  icon to  Bold ,  Italicise  and  Underline  respectively. You can also change the button text to uppercase by clicking the  change to uppercase  icon.
   • Change font and button color : 
     
     • Click the  font color picker  icon to select a font color.
     • Click the  color palette  icon to select a button color.
   • Set font size : Specify the required font size or choose one from the dropdown.
   • Set margin for button : Specify a margin in pixels for all four sides of the button.
9. You can preview the changes and close the configuration sheet. The changes will be auto saved.