Branding
Add a cover image and favicon, and remove the Formbear badge on Pro.
Cover image and favicon
Pro forms can carry a cover image, with control over its placement and width, and a custom favicon, so a shared or embedded form looks like part of your own site. On narrow screens the image collapses to a banner above the form, whichever placement you chose, so it never crowds the questions.
Removing the badge
Free forms show a small “Made with Formbear” badge. Pro can remove it. Everything else about branding, colors, fonts, and layout, is set in themes.