Once you have added a border to the object, you can easily customize the border style, color, and weight or thickness.
Here's how:
Click any object on your website page—content, image, media, apps, social, or a document.
The settings panel opens on the right side of the Website Builder.
Click the icon to open the Border settings.
Under Border Color, enter the hexadecimal value of the color, or use the color picker.
In the color picker, you can either:
Under Thickness, to specify border weight, enter the value in pixels in the field.
The object border is customized.