How to copy Footer from one layout to another

When editing a footer's layout, you can click on the 💾 icon to save a section.

Then a popup appearing allows you to rename the section and save it to the library.

Add a new footer layout or edit another one, click add a new section, and you'll see the saved section on the section library. Click on Insert to add the section to the layout.

Insert a section to the layout

The instruction of saving a section above is not only applied to the footer, you can also do the same for the header and template's layout.