How to Change Header & Footer
The header and footer either comes from theme or from elementor. If you are using direct theme version then you need to override header.php from child theme. If from elementor based header and footer layout then you can easily edit from the dashboard.
To check from where it’s coming you need to check first. So, let’s see how you can do it.
For header layout Dashboard Menu - Appearance -> Customize -> Header Panel -> Header Layout
For footer layout Dashboard Menu - Appearance -> Customize -> Footer Layout
If Theme header or theme footer then it’s coming from theme header.php file or sub template files. If Header 1, 2, 3 etc any one from these then it’s coming from elementor, same for footer. Now how it’s coming from element. See from dashboard menu UniAlumni -> Header Layout or UniAlumni -> Footer Layout
The layout you find is selected in theme customizer screen you need to edit that using elementor.