You can add an image to Totara to act as a custom background or to add an additional custom element for your certificates.
Adding a custom element:
Click the cogwheel in the upper right-hand side of Totara to open the Administration menu
Click ‘Plugins’ found under Configuration
From this plugin overview, find ‘Certificate’ and click ‘Settings’
Next, click ‘Upload’ in the Upload image section
Add your custom element to any of the sections on this page
Scroll down and click save changes
Selecting a custom element when creating your certificate in a course:
When adding or editing a certificate to a course page, find the ‘Design Options’ heading
Find the area you added the image to in part 5 of the above steps and from the drop-down, select your custom element Review your 'Certificate settings' and select 'Save and display'.