How to configure border width and colour?

[SreenivasVRao]

I'd like a white border on both the completion suggestions and the documentation.
How do I do that?

I think I need to modify company-box-frame-parameters / company-box-doc-frame-parameters...

[djs42012]

Would like to know the same!
I've tried:

(after! company-box
  (setq company-box-frame-parameters
        '((border-width . 1)
          (border-color . "#ffffff")
          (left . -1)
          (no-accept-focus . t)
          (no-focus-on-map . t)
          (min-width . 0)
          (width . 0)
          (min-height . 0)
          (height . 0)
          (internal-border-width . 3)
          (horizontal-scroll-bars)
          (left-fringe . 0)
          (right-fringe . 0)
          (menu-bar-lines . 0)
          (tool-bar-lines . 0)
          (line-spacing . 0)
          (undecorated . nil)
          (top . -1)
          (visibility)
          (mouse-wheel-frame)
          (no-other-frame . t)
          (cursor-type)
          (drag-internal-border . t)
          (left-fringe . 0)
          (right-fringe . 0)
          (tab-bar-lines . 0)
          (no-special-glyphs . t)))
          (left . -1)
          (border-color . "#ffffff")
          (no-accept-focus . t)
          (no-focus-on-map . t)
          (min-width . 0)
          (width . 0)
          (min-height . 0)
          (height . 0)
          (internal-border-width . 3)
          (horizontal-scroll-bars)
          (left-fringe . 0)
          (right-fringe . 0)
          (menu-bar-lines . 0)
          (tool-bar-lines . 0)
          (line-spacing . 0)
          (undecorated . nil)
          (top . -1)
          (visibility)
          (mouse-wheel-frame)
          (no-other-frame . t)
          (cursor-type)
          (drag-internal-border . t)
          (left-fringe . 0)
          (right-fringe . 0)
          (tab-bar-lines . 0)
          (no-special-glyphs . t))))

but no luck

[SPFabGerman]

I have the following code, that I think solves your issue:

(set-face-attribute 'child-frame-border nil :background "#ffffff")
(setq company-box-doc-frame-parameters '((left-fringe . 10) (right-fringe . 10)))

The important part is the first line, which changes the color of the border.
The second line basically just readds the fringes to the documentation window, so that the text isn't literally hugging the border, which makes it look a bit nicer.