To change the themes in GB WhatsApp Pro, follow these steps:
Open the GB WhatsApp Pro app on your device.
Click on the three dots located in the top right corner of the screen.
Select GB Settings from the drop-down menu.
Click on the Themes option.
You will see a list of available themes. Select the theme you want to use.
Click on the Apply button to apply the theme.
Note: You can also download additional themes from the internet and add them to GB WhatsApp Pro by clicking on the Download option in the Themes menu.