The Trust Bar (Recommended)
The Trust Bar Logo is the most visible variant. It scrolls with the page. Can be installed both on the left as well as right side of the screen. On mobile screens the logo is shown as icon on the bottom left or right. You can configure this yourself.
Example can be found at:
Izavie Cosmetics (German)
The Trust Bar Logo is also the easiest to install.
You just have to add the script below in the header of every page of your website: